Add DEFAULT_SUPPORT option and improve DEPENDENCIES

Signed-off-by: Mattias Andrée <m@maandree.se>

3 files changed, 45 insertions, 3 deletions

diff --git a/DEPENDENCIES b/DEPENDENCIES
index 9b6d40d..2501a5c 100644
--- a/DEPENDENCIES
+++ b/DEPENDENCIES
@@ -1,13 +1,14 @@
-Unconditional dependencies:
+Unconditional runtime dependencies:
 	libc
 
-For Argon2 support:
+For Argon2 support (runtime, build, and check dependencies):
 	libar2simplified
 	libar2
 	libblake (indirect)
 	pthread (indirect)
 
 Build dependencies:
+	libc
 	make
 	sh
 	echo
@@ -16,6 +17,11 @@ Build dependencies:
 	c99
 	ar
 
+Check dependencies:
+	libc
+	make
+	sh
+
 Install dependencies:
 	make
 	sh
@@ -31,3 +37,35 @@ Notes:
 	The Open Group Base Specifications Issue 8 (the 2024 edition);
 	strict The Open Group Base Specifications Issue 7 (the 2018 edition)
 	compliance is not sufficient.
+
+	By default, all supported algorithms are enable, however you
+	change this to disable all algorithms that are not explicitly
+	enabled by setting `DEFAULT_SUPPORT` to `false` when running
+	make(1). You can enable or disable individual algorithms by
+	setting corresponding make(1) macro to `true` (to enable)
+	or `false` (to disable). The following macros are available:
+
+		SUPPORT_ARGON2I
+			The Argon2i variant of Argon2.
+			Defaults to the value of SUPPORT_ARGON2.
+
+		SUPPORT_ARGON2D
+			The Argon2d variant of Argon2.
+			Defaults to the value of SUPPORT_ARGON2.
+
+		SUPPORT_ARGON2ID
+			The Argon2id variant of Argon2.
+			Defaults to the value of SUPPORT_ARGON2.
+
+		SUPPORT_ARGON2DS
+			The Argon2ds variant of Argon2.
+			Defaults to the value of SUPPORT_ARGON2.
+
+		SUPPORT_ARGON2
+			Default value for SUPPORT_ARGON2I,
+			SUPPORT_ARGON2D, SUPPORT_ARGON2ID, and
+			SUPPORT_ARGON2DS. Disable individual
+			algorithms can be used as a security
+			precaution, but they share dependencies,
+			so you have to disable all of them to
+			remove the dependencies listed for Argon2.
diff --git a/argon2/prefix.mk b/argon2/prefix.mk
index ff5c01d..8348a4d 100644
--- a/argon2/prefix.mk
+++ b/argon2/prefix.mk
@@ -1,4 +1,4 @@
-SUPPORT_ARGON2 = true
+SUPPORT_ARGON2 = $(DEFAULT_SUPPORT)
 
 SUPPORT_ARGON2I = $(SUPPORT_ARGON2)
 SUPPORT_ARGON2D = $(SUPPORT_ARGON2)
diff --git a/config.mk b/config.mk
index f4adf12..14bd38d 100644
--- a/config.mk
+++ b/config.mk
@@ -6,3 +6,7 @@ CC = c99
 CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700 -D_GNU_SOURCE
 CFLAGS   =
 LDFLAGS  =
+
+DEFAULT_SUPPORT = true
+# Set to "true" to enable all algorithms that are not explicitly disabled.
+# Set to "false" to disable all algorithms that are not explicitly enabled.