Hi!
I think we need some documentation on writing macros for using
libraries. In the case of GNU M4, we can use GMP, and we use the
following macro. I think it is the right way to write things, but I
would like to hear comments about it. Then I'll write the doc.
m4_define([_AC_LIB_GMP],
[AC_ARG_WITH(gmp,
[ --without-gmp don't use GNU multiple precision arithmetic library],
[use_gmp=$withval], [use_gmp=yes])
case $use_gmp:$GMP_LIB:$ac_cv_header_gmp_h in
*::yes)
AC_MSG_WARN([gmp library not found or does not appear to work
but `gmp.h' is present])
ac_cv_using_lib_gmp=no
;;
*:-lgmp:no)
AC_MSG_WARN([gmp works but `gmp.h' is missing])
ac_cv_using_lib_gmp=no
;;
yes:*:yes)
ac_cv_using_lib_gmp=yes
;;
no:*)
ac_cv_using_lib_gmp=no
;;
esac
if test "$ac_cv_using_lib_gmp" = yes; then
AC_DEFINE(WITH_GMP, 1,
[Define to 1 if the GNU multiple precision library should be used.])
fi
])# _AC_LIB_GMP
AC_DEFUN([AC_LIB_GMP],
[AC_CHECK_HEADERS([gmp.h])
AC_CHECK_LIB([gmp], [mpq_init], [GMP_LIB=-lgmp])
AC_SUBST([GMP_LIB])dnl
AC_CACHE_CHECK([if using GNU multiple precision arithmetic library],
[ac_cv_using_lib_gmp],
[_AC_LIB_GMP])
AC_SUBST([USE_GMP], [$ac_cv_using_lib_gmp])dnl
])# AC_LIB_GMP
