Configure check for GMP_NUMB_BITS.

ChangeLog

 2013-02-14  Niels Möller  <nisse@lysator.liu.se>
 
+	* configure.ac: Find GMP's GMP_NUMB_BITS. Substitute in Makefile.
+	* config.make.in (GMP_NUMB_BITS): New variable.
+
 	* examples/rsa-keygen.c (uint_arg): New function.
 	(main): New options -s and -e, to specify key size and public
 	exponent. Increased default key size to 2048.

config.make.in

@@ -46,6 +46,8 @@ LIBHOGWEED_FORLINK = @LIBHOGWEED_FORLINK@
 LIBHOGWEED_LIBS = @LIBHOGWEED_LIBS@
 LIBHOGWEED_LINK = @LIBHOGWEED_LINK@
 
+GMP_NUMB_BITS = @GMP_NUMB_BITS@
+
 AR = @AR@
 ARFLAGS = cru
 AUTOCONF = autoconf

configure.ac

@@ -587,6 +587,20 @@ Support for public key algorithms will be unavailable.])]
 # Add -R flags needed to run programs linked with gmp
 LSH_RPATH_FIX
 
+# Check for gmp limb size
+nettle_cv_gmp_numb_bits=0
+if test "$enable_public_key" = yes; then
+  AC_MSG_CHECKING([for GMP limb size])
+  AC_COMPUTE_INT(nettle_cv_gmp_numb_bits, [GMP_NUMB_BITS],
+      [#include <gmp.h>],
+      [AC_MSG_FAILURE([cannot find value of GMP_NUMB_BITS])])
+
+  AC_MSG_RESULT([$nettle_cv_gmp_numb_bits bits])
+fi
+
+GMP_NUMB_BITS="$nettle_cv_gmp_numb_bits"
+AC_SUBST([GMP_NUMB_BITS])
+
 AH_TEMPLATE([HAVE_MPZ_POWM_SEC], [Define if mpz_powm_sec is available (appeared in GMP-5)])
 AC_CHECK_FUNC(__gmpz_powm_sec, [AC_DEFINE(HAVE_MPZ_POWM_SEC)])