functions to lock and unlock pages  (3.4.3 p76)
character class determination for wide characters  (4.3 p82)
collation functions  (5.6 p109)
encode binary data  (5.11 p125)
argz and envz vectors  (5.12 p127)
characer-set handling  (6 p133)
locales and internationalisation  (7 p181)
mathematics  (8 p243)
arithmetic functions  (9 p243)
date and time  (10 p277)
message translation  (11 p315)
searching and sorting  (12 p343)
pattern matching  (13 p355)
the basic program–system interface  (14 p379)
input/output overview  (15 p429)
input/output on streams  (17 p439)

It should be possible to configure malloc, calloc, and
realloc to allocate some extra space. This is usable
for single-threaded allocations; they do not need to
realloc strings returned by functions with
__attribute__((malloc)), to append a string or character.


LOW PRIORITY:
  debugging support  (16 p435)
    _GNU_SOURCE, system-dependant