# libgmp.m4 serial 4
# Configure the GMP library or a replacement.
dnl Copyright 2020 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

dnl gl_LIBGMP
dnl Search for an installed libgmp.
dnl If found, set and AC_SUBST HAVE_LIBGMP=yes and the LIBGMP and LTLIBGMP
dnl variables, and augment the CPPFLAGS variable, and #define HAVE_LIBGMP to 1.
dnl Otherwise, set and AC_SUBST HAVE_LIBGMP=no and LIBGMP and LTLIBGMP to
dnl empty.

AC_DEFUN([gl_LIBGMP],
[
  AC_ARG_WITH([libgmp],
    [AS_HELP_STRING([--without-libgmp],
       [do not use the GNU Multiple Precision (GMP) library;
        this is the default on systems lacking libgmp.])])
  case "$with_libgmp" in
    no)
      HAVE_LIBGMP=no
      LIBGMP=
      LTLIBGMP=
      ;;
    *)
      dnl Prefer AC_LIB_HAVE_LINKFLAGS if the havelib module is also in use.
      m4_ifdef([gl_HAVE_MODULE_HAVELIB],
        [AC_LIB_HAVE_LINKFLAGS([gmp], [],
           [#include <gmp.h>],
           [static const mp_limb_t x[2] = { 0x73, 0x55 };
            mpz_t tmp;
            mpz_roinit_n (tmp, x, 2);
           ],
           [no])],
        [gl_saved_LIBS=$LIBS
         AC_SEARCH_LIBS([__gmpz_roinit_n], [gmp])
         LIBS=$gl_saved_LIBS
         case $ac_cv_search___gmpz_roinit_n in
           'none needed')
             HAVE_LIBGMP=yes LIBGMP=;;
           -*)
             HAVE_LIBGMP=yes LIBGMP=$ac_cv_search___gmpz_roinit_n;;
           *)
             HAVE_LIBGMP=no LIBGMP=;;
         esac
         LTLIBGMP=$LIBGMP
         AC_SUBST([HAVE_LIBGMP])
         AC_SUBST([LIBGMP])
         AC_SUBST([LTLIBGMP])])
      if test "$with_libgmp,$HAVE_LIBGMP" = yes,no; then
        AC_MSG_ERROR(
          [GMP not found, although --with-libgmp was specified.m4_ifdef(
             [AC_LIB_HAVE_LINKFLAGS],
             [ Try specifying --with-libgmp-prefix=DIR.])])
      fi
      ;;
  esac
  if test $HAVE_LIBGMP = yes; then
    GMP_H=
  else
    GMP_H=gmp.h
  fi
  AC_SUBST([GMP_H])
  AM_CONDITIONAL([GL_GENERATE_GMP_H], [test -n "$GMP_H"])
])