attributes are gcc specific

Signed-off-by: Mattias Andrée <maandree@operamail.com>

9 files changed, 125 insertions, 54 deletions

diff --git a/Makefile b/Makefile
index f0b7008..0d27baa 100644
--- a/Makefile
+++ b/Makefile
@@ -74,7 +74,7 @@ lib: so a
 .PHONY: so
 so: bin/libkeccak.so.$(LIB_VERSION) bin/libkeccak.so.$(LIB_MAJOR) bin/libkeccak.so
 
-obj/libkeccak/%.o: src/libkeccak/%.c src/libkeccak.h src/libkeccak/*.h
+obj/libkeccak/%.o: src/libkeccak/%.c src/libkeccak.h src/libkeccak/*.h src/libkeccak/*/*.h
 	@mkdir -p $$(dirname $@)
 	$(CC) $(FLAGS) $(COPTIMISE) -fPIC -c -o $@ $< $(CFLAGS) $(CPPFLAGS)
 
@@ -203,6 +203,7 @@ install-headers:
 	install -m644 -- src/libkeccak/hex.h "$(DESTDIR)$(INCLUDEDIR)/libkeccak/hex.h"
 	install -m644 -- src/libkeccak/spec.h "$(DESTDIR)$(INCLUDEDIR)/libkeccak/spec.h"
 	install -m644 -- src/libkeccak/state.h "$(DESTDIR)$(INCLUDEDIR)/libkeccak/state.h"
+	install -m644 -- src/libkeccak/internal.h "$(DESTDIR)$(INCLUDEDIR)/libkeccak/internal.h"
 	install -m644 -- src/libkeccak/mac/hmac.h "$(DESTDIR)$(INCLUDEDIR)/libkeccak/mac/hmac.h"
 
 .PHONY: install-dynamic-lib
@@ -263,6 +264,7 @@ uninstall:
 	-rm -- "$(DESTDIR)$(INCLUDEDIR)/libkeccak/hex.h"
 	-rm -- "$(DESTDIR)$(INCLUDEDIR)/libkeccak/spec.h"
 	-rm -- "$(DESTDIR)$(INCLUDEDIR)/libkeccak/state.h"
+	-rm -- "$(DESTDIR)$(INCLUDEDIR)/libkeccak/internal.h"
 	-rm -- "$(DESTDIR)$(INCLUDEDIR)/libkeccak/mac/hmac.h"
 	-rmdir -- "$(DESTDIR)$(INCLUDEDIR)/libkeccak/mac"
 	-rmdir -- "$(DESTDIR)$(INCLUDEDIR)/libkeccak"
diff --git a/src/libkeccak/digest.h b/src/libkeccak/digest.h
index 8a69fdb..51a5a6c 100644
--- a/src/libkeccak/digest.h
+++ b/src/libkeccak/digest.h
@@ -21,6 +21,7 @@
 
 
 #include "state.h"
+#include "internal.h"
 
 
 /**
@@ -32,7 +33,7 @@
  * @param   msglen  The length of the partial message
  * @return          Zero on success, -1 on error
  */
-__attribute__((nonnull))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull)))
 int libkeccak_fast_update(libkeccak_state_t* restrict state, const char* restrict msg, size_t msglen);
 
 
@@ -45,7 +46,7 @@ int libkeccak_fast_update(libkeccak_state_t* restrict state, const char* restric
  * @param   msglen  The length of the partial message
  * @return          Zero on success, -1 on error
  */
-__attribute__((nonnull))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull)))
 int libkeccak_update(libkeccak_state_t* restrict state, const char* restrict msg, size_t msglen);
 
 
@@ -61,7 +62,7 @@ int libkeccak_update(libkeccak_state_t* restrict state, const char* restrict msg
  * @param   hashsum  Output parameter for the hashsum, may be `NULL`
  * @return           Zero on success, -1 on error
  */
-__attribute__((nonnull(1)))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(1))))
 int libkeccak_fast_digest(libkeccak_state_t* restrict state, const char* restrict msg, size_t msglen,
 			  size_t bits, const char* restrict suffix, char* restrict hashsum);
 
@@ -78,7 +79,7 @@ int libkeccak_fast_digest(libkeccak_state_t* restrict state, const char* restric
  * @param   hashsum  Output parameter for the hashsum, may be `NULL`
  * @return           Zero on success, -1 on error
  */
-__attribute__((nonnull(1)))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(1))))
 int libkeccak_digest(libkeccak_state_t* restrict state, const char* restrict msg, size_t msglen,
 		     size_t bits, const char* restrict suffix, char* restrict hashsum);
 
@@ -89,7 +90,7 @@ int libkeccak_digest(libkeccak_state_t* restrict state, const char* restrict msg
  * @param  state  The hashing state
  * @param  times  The number of rounds
  */
-__attribute__((nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow)))
 void libkeccak_simple_squeeze(register libkeccak_state_t* restrict state, register long times);
 
 
@@ -99,7 +100,7 @@ void libkeccak_simple_squeeze(register libkeccak_state_t* restrict state, regist
  * @param  state  The hashing state
  * @param  times  The number of digests
  */
-__attribute__((nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow)))
 void libkeccak_fast_squeeze(register libkeccak_state_t* restrict state, register long times);
 
 
@@ -109,7 +110,7 @@ void libkeccak_fast_squeeze(register libkeccak_state_t* restrict state, register
  * @param  state    The hashing state
  * @param  hashsum  Output parameter for the hashsum
  */
-__attribute__((nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow)))
 void libkeccak_squeeze(register libkeccak_state_t* restrict state, register char* restrict hashsum);
 
 
diff --git a/src/libkeccak/files.h b/src/libkeccak/files.h
index 91b25dd..5a0b159 100644
--- a/src/libkeccak/files.h
+++ b/src/libkeccak/files.h
@@ -21,6 +21,7 @@
 
 
 #include "../libkeccak.h"
+#include "internal.h"
 
 
 /**
@@ -35,7 +36,7 @@
  *                   at least `(spec->output / 8) * sizeof(char)`, may be `NULL`
  * @return           Zero on success, -1 on error
  */
-__attribute__((nonnull(2, 3)))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(2, 3))))
 int libkeccak_generalised_sum_fd(int fd, libkeccak_state_t* restrict state,
 				 const libkeccak_spec_t* restrict spec,
 				 const char* restrict suffix, char* restrict hashsum);
@@ -52,7 +53,8 @@ int libkeccak_generalised_sum_fd(int fd, libkeccak_state_t* restrict state,
  *                   at least `(spec->output / 8) * sizeof(char)`, may be `NULL`
  * @return           Zero on success, -1 on error
  */
-static inline __attribute__((nonnull(2, 3), artificial, gnu_inline))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(2, 3), artificial, gnu_inline)))
+static inline
 int libkeccak_keccaksum_fd(int fd, libkeccak_state_t* restrict state,
 			   const libkeccak_spec_t* restrict spec, char* restrict hashsum)
 {
@@ -71,7 +73,8 @@ int libkeccak_keccaksum_fd(int fd, libkeccak_state_t* restrict state,
  *                   at least `(output / 8) * sizeof(char)`, may be `NULL`
  * @return           Zero on success, -1 on error
  */
-static inline __attribute__((nonnull(2), artificial, gnu_inline))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(2), artificial, gnu_inline)))
+static inline
 int libkeccak_sha3sum_fd(int fd, libkeccak_state_t* restrict state,
 			 long output, char* restrict hashsum)
 {
@@ -93,7 +96,8 @@ int libkeccak_sha3sum_fd(int fd, libkeccak_state_t* restrict state,
  *                        at least `(output / 8) * sizeof(char)`, may be `NULL`
  * @return                Zero on success, -1 on error
  */
-static inline __attribute__((nonnull(2), artificial, gnu_inline))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(2), artificial, gnu_inline)))
+static inline
 int libkeccak_rawshakesum_fd(int fd, libkeccak_state_t* restrict state,
 			     long semicapacity, long output, char* restrict hashsum)
 {
@@ -115,7 +119,8 @@ int libkeccak_rawshakesum_fd(int fd, libkeccak_state_t* restrict state,
  *                        at least `(output / 8) * sizeof(char)`, may be `NULL`
  * @return                Zero on success, -1 on error
  */
-static inline __attribute__((nonnull(2), artificial, gnu_inline))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(2), artificial, gnu_inline)))
+static inline
 int libkeccak_shakesum_fd(int fd, libkeccak_state_t* restrict state,
 			  long semicapacity, long output, char* restrict hashsum)
 {
diff --git a/src/libkeccak/generalised-spec.h b/src/libkeccak/generalised-spec.h
index 538c260..1bcfc57 100644
--- a/src/libkeccak/generalised-spec.h
+++ b/src/libkeccak/generalised-spec.h
@@ -21,6 +21,7 @@
 
 
 #include "spec.h"
+#include "internal.h"
 
 #include <inttypes.h>
 
@@ -131,7 +132,8 @@ typedef struct libkeccak_generalised_spec
  * 
  * @param  spec  The specification datastructure to fill in
  */
-static inline __attribute__((nonnull, nothrow, unused))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow, unused)))
+static inline
 void libkeccak_generalised_spec_initialise(libkeccak_generalised_spec_t* restrict spec)
 {
   spec->bitrate    = LIBKECCAK_GENERALISED_SPEC_AUTOMATIC;
@@ -149,7 +151,7 @@ void libkeccak_generalised_spec_initialise(libkeccak_generalised_spec_t* restric
  * @param   output_spec  The specification datastructure to fill in
  * @return               Zero if `spec` is valid, a `LIBKECCAK_GENERALISED_SPEC_ERROR_*` if an error was found
  */
-__attribute__((leaf, nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull, nothrow)))
 int libkeccak_degeneralise_spec(libkeccak_generalised_spec_t* restrict spec,
 				libkeccak_spec_t* restrict output_spec);
 
diff --git a/src/libkeccak/hex.h b/src/libkeccak/hex.h
index 58e07f8..793f4a1 100644
--- a/src/libkeccak/hex.h
+++ b/src/libkeccak/hex.h
@@ -20,6 +20,8 @@
 #define LIBKECCAK_HEX_H  1
 
 
+#include "internal.h"
+
 #include <stddef.h>
 
 
@@ -30,7 +32,7 @@
  * @param  hashsum  The hashsum to convert
  * @param  n        The size of `hashsum`
  */
-__attribute__((leaf, nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull, nothrow)))
 void libkeccak_behex_lower(char* restrict output, const char* restrict hashsum, size_t n);
 
 
@@ -41,7 +43,7 @@ void libkeccak_behex_lower(char* restrict output, const char* restrict hashsum,
  * @param  hashsum  The hashsum to convert
  * @param  n        The size of `hashsum`
  */
-__attribute__((leaf, nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull, nothrow)))
 void libkeccak_behex_upper(char* restrict output, const char* restrict hashsum, size_t n);
 
 
@@ -52,7 +54,7 @@ void libkeccak_behex_upper(char* restrict output, const char* restrict hashsum,
  * @param  output   Output array, should have an allocation size of at least `strlen(hashsum) / 2`
  * @param  hashsum  The hashsum to convert
  */
-__attribute__((leaf, nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull, nothrow)))
 void libkeccak_unhex(char* restrict output, const char* restrict hashsum);
 
 
diff --git a/src/libkeccak/internal.h b/src/libkeccak/internal.h
new file mode 100644
index 0000000..69bc470
--- /dev/null
+++ b/src/libkeccak/internal.h
@@ -0,0 +1,35 @@
+/**
+ * libkeccak – Keccak-family hashing library
+ * 
+ * Copyright © 2014, 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef LIBKECCAK_INTERNAL_H
+#define LIBKECCAK_INTERNAL_H  1
+
+
+/**
+ * Only include some C code (not for CPP directives)
+ * if compiling with GCC.
+ */
+#ifdef __GNUC__
+# define LIBKECCAK_GCC_ONLY(x)  x
+#else
+# define LIBKECCAK_GCC_ONLY(x)
+#endif
+
+
+#endif
+
diff --git a/src/libkeccak/mac/hmac.h b/src/libkeccak/mac/hmac.h
index 2b4b264..f85bd3b 100644
--- a/src/libkeccak/mac/hmac.h
+++ b/src/libkeccak/mac/hmac.h
@@ -28,6 +28,7 @@
 
 #include "../spec.h"
 #include "../state.h"
+#include "../internal.h"
 
 #include <stddef.h>
 #include <stdint.h>
@@ -94,7 +95,7 @@ typedef struct libkeccak_hmac_state
  * @param   key_length  The length of key, in bits
  * @return              Zero on success, -1 on error
  */
-__attribute__((nonnull(1), unused))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(1), unused)))
 int libkeccak_hmac_set_key(libkeccak_hmac_state_t* restrict state, const char* restrict key, size_t key_length);
 
 
@@ -107,7 +108,8 @@ int libkeccak_hmac_set_key(libkeccak_hmac_state_t* restrict state, const char* r
  * @param   key_length  The length of key, in bits
  * @return              Zero on success, -1 on error
  */
-static inline __attribute__((nonnull))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull)))
+static inline
 int libkeccak_hmac_initialise(libkeccak_hmac_state_t* restrict state, const libkeccak_spec_t* restrict spec,
 			      const char* restrict key, size_t key_length)
 {
@@ -131,7 +133,8 @@ int libkeccak_hmac_initialise(libkeccak_hmac_state_t* restrict state, const libk
  * @param   key_length  The length of key, in bits
  * @return              The state, `NULL` on error
  */
-static inline __attribute__((nonnull, unused, warn_unused_result, malloc))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, unused, warn_unused_result, malloc)))
+static inline
 libkeccak_hmac_state_t* libkeccak_hmac_create(const libkeccak_spec_t* restrict spec,
 					      const char* restrict key, size_t key_length)
 {
@@ -152,7 +155,8 @@ libkeccak_hmac_state_t* libkeccak_hmac_create(const libkeccak_spec_t* restrict s
  * @param   key_length  The length of key, in bits, ignored if `key == NULL`
  * @return              Zero on success, -1 on error
  */
-static inline __attribute__((nonnull(1), unused))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(1), unused)))
+static inline
 int libkeccak_hmac_reset(libkeccak_hmac_state_t* restrict state, const char* restrict key, size_t key_length)
 {
   libkeccak_state_reset(&(state->sponge));
@@ -165,7 +169,7 @@ int libkeccak_hmac_reset(libkeccak_hmac_state_t* restrict state, const char* res
  * 
  * @param  state  The state that should be wipe
  */
-__attribute__((nonnull, nothrow, optimize("-O0")))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow, optimize("-O0"))))
 void libkeccak_hmac_wipe(volatile libkeccak_hmac_state_t* restrict state);
 
 
@@ -194,7 +198,8 @@ void libkeccak_hmac_fast_destroy(libkeccak_hmac_state_t* restrict state)
  * 
  * @param  state  The state that should be destroyed
  */
-static inline __attribute__((unused, optimize("-O0")))
+LIBKECCAK_GCC_ONLY(__attribute__((unused, optimize("-O0"))))
+static inline
 void libkeccak_hmac_destroy(volatile libkeccak_hmac_state_t* restrict state)
 {
   if (state == NULL)
@@ -216,7 +221,8 @@ void libkeccak_hmac_destroy(volatile libkeccak_hmac_state_t* restrict state)
  * 
  * @param  state  The state that should be freed
  */
-static inline __attribute__((unused))
+LIBKECCAK_GCC_ONLY(__attribute__((unused)))
+static inline
 void libkeccak_hmac_fast_free(libkeccak_hmac_state_t* restrict state)
 {
   libkeccak_hmac_fast_destroy(state);
@@ -229,7 +235,8 @@ void libkeccak_hmac_fast_free(libkeccak_hmac_state_t* restrict state)
  * 
  * @param  state  The state that should be freed
  */
-static inline __attribute__((unused, optimize("-O0")))
+LIBKECCAK_GCC_ONLY(__attribute__((unused, optimize("-O0"))))
+static inline
 void libkeccak_hmac_free(volatile libkeccak_hmac_state_t* restrict state)
 {
 #ifdef __GNUC__
@@ -251,7 +258,7 @@ void libkeccak_hmac_free(volatile libkeccak_hmac_state_t* restrict state)
  * @param   src   The state to duplicate
  * @return        Zero on success, -1 on error
  */
-__attribute__((nonnull))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull)))
 int libkeccak_hmac_copy(libkeccak_hmac_state_t* restrict dest, const libkeccak_hmac_state_t* restrict src);
 
 
@@ -261,7 +268,8 @@ int libkeccak_hmac_copy(libkeccak_hmac_state_t* restrict dest, const libkeccak_h
  * @param   src  The state to duplicate
  * @return       The duplicate, `NULL` on error
  */
-static inline __attribute__((nonnull, unused, warn_unused_result, malloc))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, unused, warn_unused_result, malloc)))
+static inline
 libkeccak_hmac_state_t* libkeccak_hmac_duplicate(const libkeccak_hmac_state_t* restrict src)
 {
   libkeccak_hmac_state_t* restrict dest = malloc(sizeof(libkeccak_hmac_state_t));
@@ -279,7 +287,8 @@ libkeccak_hmac_state_t* libkeccak_hmac_duplicate(const libkeccak_hmac_state_t* r
  * @param   state  The state as it will be marshalled by a subsequent call to `libkeccak_hamc_marshal`
  * @return         The allocation size needed for the buffer to which the state will be marshalled
  */
-static inline __attribute__((nonnull, nothrow, unused, warn_unused_result, pure))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow, unused, warn_unused_result, pure)))
+static inline
 size_t libkeccak_hmac_marshal_size(const libkeccak_hmac_state_t* restrict state)
 {
   return libkeccak_state_marshal_size(&(state->sponge)) + sizeof(size_t) +
@@ -294,7 +303,8 @@ size_t libkeccak_hmac_marshal_size(const libkeccak_hmac_state_t* restrict state)
  * @param   data   The output buffer
  * @return         The number of bytes stored to `data`
  */
-static inline __attribute__((nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow)))
+static inline
 size_t libkeccak_hmac_marshal(const libkeccak_hmac_state_t* restrict state, char* restrict data)
 {
   size_t written = libkeccak_state_marshal(&(state->sponge), data);
@@ -316,7 +326,7 @@ size_t libkeccak_hmac_marshal(const libkeccak_hmac_state_t* restrict state, char
  * @param   data   The input buffer
  * @return         The number of bytes read from `data`, 0 on error
  */
-__attribute__((nonnull))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull)))
 size_t libkeccak_hmac_unmarshal(libkeccak_hmac_state_t* restrict state, const char* restrict data);
 
 
@@ -327,7 +337,8 @@ size_t libkeccak_hmac_unmarshal(libkeccak_hmac_state_t* restrict state, const ch
  * @param   data  The data buffer
  * @return        The byte size of the stored state
  */
-static inline __attribute__((nonnull, nothrow, warn_unused_result, pure))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow, warn_unused_result, pure)))
+static inline
 size_t libkeccak_hmac_unmarshal_skip(const char* restrict data)
 {
   size_t skip = libkeccak_state_unmarshal_skip(data);
@@ -345,7 +356,7 @@ size_t libkeccak_hmac_unmarshal_skip(const char* restrict data)
  * @param   msglen  The length of the partial message, in bytes
  * @return          Zero on success, -1 on error
  */
-__attribute__((nonnull(1)))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(1))))
 int libkeccak_hmac_fast_update(libkeccak_hmac_state_t* restrict state, const char* restrict msg, size_t msglen);
 
 
@@ -358,7 +369,7 @@ int libkeccak_hmac_fast_update(libkeccak_hmac_state_t* restrict state, const cha
  * @param   msglen  The length of the partial message, in bytes
  * @return          Zero on success, -1 on error
  */
-__attribute__((nonnull(1)))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(1))))
 int libkeccak_hmac_update(libkeccak_hmac_state_t* restrict state, const char* restrict msg, size_t msglen);
 
 
@@ -376,7 +387,7 @@ int libkeccak_hmac_update(libkeccak_hmac_state_t* restrict state, const char* re
  * @param   hashsum  Output parameter for the hashsum, may be `NULL`
  * @return           Zero on success, -1 on error
  */
-__attribute__((nonnull(1)))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(1))))
 int libkeccak_hmac_fast_digest(libkeccak_hmac_state_t* restrict state, const char* restrict msg, size_t msglen,
 			       size_t bits, const char* restrict suffix, char* restrict hashsum);
 
@@ -395,7 +406,7 @@ int libkeccak_hmac_fast_digest(libkeccak_hmac_state_t* restrict state, const cha
  * @param   hashsum  Output parameter for the hashsum, may be `NULL`
  * @return           Zero on success, -1 on error
  */
-__attribute__((nonnull(1)))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull(1))))
 int libkeccak_hmac_digest(libkeccak_hmac_state_t* restrict state, const char* restrict msg, size_t msglen,
 			  size_t bits, const char* restrict suffix, char* restrict hashsum);
 
diff --git a/src/libkeccak/spec.h b/src/libkeccak/spec.h
index 3e14f8e..3faecf2 100644
--- a/src/libkeccak/spec.h
+++ b/src/libkeccak/spec.h
@@ -20,6 +20,8 @@
 #define LIBKECCAK_SPEC_H  1
 
 
+#include "internal.h"
+
 #include <stdint.h>
 #include <limits.h>
 
@@ -123,7 +125,8 @@ typedef struct libkeccak_spec
  * @param  spec  The specifications datastructure to fill in
  * @param  x     The value of x in `SHA3-x`, the output size
  */
-static inline __attribute__((nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow)))
+static inline
 void libkeccak_spec_sha3(libkeccak_spec_t* restrict spec, long x)
 {
   spec->bitrate = 1600 - 2 * x;
@@ -139,7 +142,8 @@ void libkeccak_spec_sha3(libkeccak_spec_t* restrict spec, long x)
  * @param  x     The value of x in `RawSHAKEx`, half the capacity
  * @param  d     The output size
  */
-static inline __attribute__((nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow)))
+static inline
 void libkeccak_spec_rawshake(libkeccak_spec_t* restrict spec, long x, long d)
 {
   spec->bitrate = 1600 - 2 * x;
@@ -164,7 +168,8 @@ void libkeccak_spec_rawshake(libkeccak_spec_t* restrict spec, long x, long d)
  * @param   spec  The specifications datastructure to check
  * @return        Zero if error free, a `LIBKECCAK_SPEC_ERROR_*` if an error was found
  */
-static inline __attribute__((nonnull, nothrow, unused, warn_unused_result, pure))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow, unused, warn_unused_result, pure)))
+static inline
 int libkeccak_spec_check(const libkeccak_spec_t* restrict spec)
 {
   long state_size = spec->capacity + spec->bitrate;
diff --git a/src/libkeccak/state.h b/src/libkeccak/state.h
index 4c2c1d8..6bf19f7 100644
--- a/src/libkeccak/state.h
+++ b/src/libkeccak/state.h
@@ -21,6 +21,7 @@
 
 
 #include "spec.h"
+#include "internal.h"
 
 #include <stddef.h>
 #include <stdint.h>
@@ -108,7 +109,7 @@ typedef struct libkeccak_state
  * @param   spec   The specifications for the state
  * @return         Zero on success, -1 on error
  */
-__attribute__((leaf, nonnull))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull)))
 int libkeccak_state_initialise(libkeccak_state_t* restrict state, const libkeccak_spec_t* restrict spec);
 
 
@@ -117,7 +118,8 @@ int libkeccak_state_initialise(libkeccak_state_t* restrict state, const libkecca
  * 
  * @param  state  The state that should be reset
  */
-static inline __attribute__((nonnull, nothrow, unused))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow, unused)))
+static inline
 void libkeccak_state_reset(libkeccak_state_t* restrict state)
 {
   state->mptr = 0;
@@ -145,7 +147,7 @@ void libkeccak_state_fast_destroy(libkeccak_state_t* restrict state)
  * 
  * @param  state  The state that should be wipe
  */
-__attribute__((leaf, nonnull, nothrow, optimize("-O0")))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull, nothrow, optimize("-O0"))))
 void libkeccak_state_wipe_message(volatile libkeccak_state_t* restrict state);
 
 /**
@@ -153,7 +155,7 @@ void libkeccak_state_wipe_message(volatile libkeccak_state_t* restrict state);
  * 
  * @param  state  The state that should be wipe
  */
-__attribute__((leaf, nonnull, nothrow, optimize("-O0")))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull, nothrow, optimize("-O0"))))
 void libkeccak_state_wipe_sponge(volatile libkeccak_state_t* restrict state);
 
 /**
@@ -161,7 +163,7 @@ void libkeccak_state_wipe_sponge(volatile libkeccak_state_t* restrict state);
  * 
  * @param  state  The state that should be wipe
  */
-__attribute__((nonnull, nothrow, optimize("-O0")))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow, optimize("-O0"))))
 void libkeccak_state_wipe(volatile libkeccak_state_t* restrict state);
 
 
@@ -170,7 +172,8 @@ void libkeccak_state_wipe(volatile libkeccak_state_t* restrict state);
  * 
  * @param  state  The state that should be destroyed
  */
-static inline __attribute__((unused, optimize("-O0")))
+LIBKECCAK_GCC_ONLY(__attribute__((unused, optimize("-O0"))))
+static inline
 void libkeccak_state_destroy(volatile libkeccak_state_t* restrict state)
 {
   if (state == NULL)
@@ -187,7 +190,8 @@ void libkeccak_state_destroy(volatile libkeccak_state_t* restrict state)
  * @param   spec  The specifications for the state
  * @return        The state, `NULL` on error
  */
-static inline __attribute__((nonnull, unused, warn_unused_result, malloc))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, unused, warn_unused_result, malloc)))
+static inline
 libkeccak_state_t* libkeccak_state_create(const libkeccak_spec_t* restrict spec)
 {
   libkeccak_state_t* restrict state = malloc(sizeof(libkeccak_state_t));
@@ -203,7 +207,8 @@ libkeccak_state_t* libkeccak_state_create(const libkeccak_spec_t* restrict spec)
  * 
  * @param  state  The state that should be freed
  */
-static inline __attribute__((unused))
+LIBKECCAK_GCC_ONLY(__attribute__((unused)))
+static inline
 void libkeccak_state_fast_free(libkeccak_state_t* restrict state)
 {
   libkeccak_state_fast_destroy(state);
@@ -216,7 +221,8 @@ void libkeccak_state_fast_free(libkeccak_state_t* restrict state)
  * 
  * @param  state  The state that should be freed
  */
-static inline __attribute__((unused, optimize("-O0")))
+LIBKECCAK_GCC_ONLY(__attribute__((unused, optimize("-O0"))))
+static inline
 void libkeccak_state_free(volatile libkeccak_state_t* restrict state)
 {
 #ifdef __GNUC__
@@ -238,7 +244,7 @@ void libkeccak_state_free(volatile libkeccak_state_t* restrict state)
  * @param   src   The state to duplicate
  * @return        Zero on success, -1 on error
  */
-__attribute__((leaf, nonnull))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull)))
 int libkeccak_state_copy(libkeccak_state_t* restrict dest, const libkeccak_state_t* restrict src);
 
 
@@ -248,7 +254,8 @@ int libkeccak_state_copy(libkeccak_state_t* restrict dest, const libkeccak_state
  * @param   src  The state to duplicate
  * @return       The duplicate, `NULL` on error
  */
-static inline __attribute__((nonnull, unused, warn_unused_result, malloc))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, unused, warn_unused_result, malloc)))
+static inline
 libkeccak_state_t* libkeccak_state_duplicate(const libkeccak_state_t* restrict src)
 {
   libkeccak_state_t* restrict dest = malloc(sizeof(libkeccak_state_t));
@@ -266,7 +273,8 @@ libkeccak_state_t* libkeccak_state_duplicate(const libkeccak_state_t* restrict s
  * @param   state  The state as it will be marshalled by a subsequent call to `libkeccak_state_marshal`
  * @return         The allocation size needed for the buffer to which the state will be marshalled
  */
-static inline __attribute__((nonnull, nothrow, unused, warn_unused_result, pure))
+LIBKECCAK_GCC_ONLY(__attribute__((nonnull, nothrow, unused, warn_unused_result, pure)))
+static inline
 size_t libkeccak_state_marshal_size(const libkeccak_state_t* restrict state)
 {
   return sizeof(libkeccak_state_t) - sizeof(char*) + state->mptr * sizeof(char);
@@ -280,7 +288,7 @@ size_t libkeccak_state_marshal_size(const libkeccak_state_t* restrict state)
  * @param   data   The output buffer
  * @return         The number of bytes stored to `data`
  */
-__attribute__((leaf, nonnull, nothrow))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull, nothrow)))
 size_t libkeccak_state_marshal(const libkeccak_state_t* restrict state, char* restrict data);
 
 
@@ -291,7 +299,7 @@ size_t libkeccak_state_marshal(const libkeccak_state_t* restrict state, char* re
  * @param   data   The input buffer
  * @return         The number of bytes read from `data`, 0 on error
  */
-__attribute__((leaf, nonnull))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull)))
 size_t libkeccak_state_unmarshal(libkeccak_state_t* restrict state, const char* restrict data);
 
 
@@ -302,7 +310,7 @@ size_t libkeccak_state_unmarshal(libkeccak_state_t* restrict state, const char*
  * @param   data  The data buffer
  * @return        The byte size of the stored state
  */
-__attribute__((leaf, nonnull, nothrow, warn_unused_result, pure))
+LIBKECCAK_GCC_ONLY(__attribute__((leaf, nonnull, nothrow, warn_unused_result, pure)))
 size_t libkeccak_state_unmarshal_skip(const char* restrict data);