+ACX_PROG_CMP_IGNORE_INITIAL
+
+# Check for GMP
+gmplibs=
+gmpinc=
+have_gmp=yes
+# Specify a location for gmp
+AC_ARG_WITH(gmp-dir, [ --with-gmp-dir=PATH Specify source directory for GMP library])
+
+if test "x$with_gmp_dir" != x && test -f "$with_gmp_dir/gmp.h"; then
+ gmpinc="-I$with_gmp_dir"
+ if test -f "$with_gmp_dir/.libs/libgmp.a"; then
+ gmplibs="$with_gmp_dir/.libs/libgmp.a"
+ elif test -f "$with_gmp_dir/_libs/libgmp.a"; then
+ gmplibs="$with_gmp_dir/_libs/libgmp.a"
+ fi
+ # One of the later tests will catch the error if neither library is present.
+fi
+
+AC_ARG_WITH(gmp, [ --with-gmp=PATH Specify directory for installed GMP library])
+
+if test "x$with_gmp" != x && test -d "$with_gmp"; then
+ gmplibs="-L$with_gmp/lib -lgmp"
+ gmpinc="-I$with_gmp/include"
+fi
+
+# Use system gmp if nothing else specified
+if test "x$gmplibs" = x; then
+ gmplibs="-lgmp"
+fi
+
+saved_CFLAGS="$CFLAGS"
+CFLAGS="$CFLAGS $gmpinc"
+# Check GMP actually works
+AC_MSG_CHECKING([for correct version of gmp.h])
+AC_TRY_COMPILE([#include "gmp.h"],[
+#if __GNU_MP_VERSION < 3
+choke me
+#endif
+], [AC_MSG_RESULT([yes])],
+ [AC_MSG_RESULT([no]); have_gmp=no])
+
+if test x"$have_gmp" = xyes; then
+ AC_MSG_CHECKING([for mpf_init in -lgmp])
+
+ saved_LIBS="$LIBS"
+ LIBS="$LIBS $gmplibs"
+ AC_TRY_LINK([#include <gmp.h>], [mpf_t n; mpf_init(n);],
+ [AC_MSG_RESULT([yes])], [AC_MSG_RESULT([no]); have_gmp=no])
+ LIBS="$saved_LIBS"
+ CFLAGS="$saved_CFLAGS"
+fi
+
+AC_SUBST(gmplibs)
+AC_SUBST(gmpinc)