The following macros check for certain operating systems that need special treatment for some programs, due to exceptional oddities in their header files or libraries. These macros are warts; they will be replaced by a more systematic approach, based on the functions they make available or the environments they provide.
_ALL_SOURCE.  Allows the use of some BSD
functions.  Should be called before any macros that run the C compiler.
LIBS.  This macro is obsolete; instead, use
AC_FUNC_GETMNTENT.
LIBS.  This macro is obsolete.  If you were using it to get
getmntent, use AC_FUNC_GETMNTENT instead.  If you used it
for the NIS versions of the password and group functions, use
`AC_CHECK_LIB(sun, getpwnam)'.
_POSIX_SOURCE and add
`-posix' (for the GNU C compiler) or `-Xp' (for other C
compilers) to output variable CC.  This allows the use of
POSIX facilities.  Must be called after AC_PROG_CC and before
any other macros that run the C compiler.
_MINIX and _POSIX_SOURCE and define
_POSIX_1_SOURCE to be 2.  This allows the use of POSIX
facilities.  Should be called before any macros that run the C compiler.
LIBS.
This macro is obsolete; instead, use AC_FUNC_STRFTIME.
LIBS.  Also, if
`dirent.h' is being used, add `-ldir' to LIBS.  This
macro is obsolete; use AC_HEADER_DIRENT instead.
Go to the first, previous, next, last section, table of contents.