Update libgcrypt autoconf macros from upstream

m4/libgcrypt.m4

@@ -1,5 +1,5 @@
 dnl Autoconf macros for libgcrypt
-dnl       Copyright (C) 2002, 2004 Free Software Foundation, Inc.
+dnl       Copyright (C) 2002, 2004, 2011 Free Software Foundation, Inc.
 dnl
 dnl This file is free software; as a special exception the author gives
 dnl unlimited permission to copy and/or distribute it, with or without
@@ -15,13 +15,14 @@ dnl                   [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND ]]])
 dnl Test for libgcrypt and define LIBGCRYPT_CFLAGS and LIBGCRYPT_LIBS.
 dnl MINIMUN-VERSION is a string with the version number optionalliy prefixed
 dnl with the API version to also check the API compatibility. Example:
-dnl a MINIMUN-VERSION of 1:1.2.5 won't pass the test unless the installed 
+dnl a MINIMUN-VERSION of 1:1.2.5 won't pass the test unless the installed
 dnl version of libgcrypt is at least 1.2.5 *and* the API number is 1.  Using
 dnl this features allows to prevent build against newer versions of libgcrypt
 dnl with a changed API.
 dnl
 AC_DEFUN([AM_PATH_LIBGCRYPT],
-[ AC_ARG_WITH(libgcrypt-prefix,
+[ AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_ARG_WITH(libgcrypt-prefix,
             AC_HELP_STRING([--with-libgcrypt-prefix=PFX],
                            [prefix where LIBGCRYPT is installed (optional)]),
      libgcrypt_config_prefix="$withval", libgcrypt_config_prefix="")
@@ -31,7 +32,7 @@ AC_DEFUN([AM_PATH_LIBGCRYPT],
      fi
   fi
 
-  AC_PATH_PROG(LIBGCRYPT_CONFIG, libgcrypt-config, no)
+  AC_PATH_TOOL(LIBGCRYPT_CONFIG, libgcrypt-config, no)
   tmp=ifelse([$1], ,1:1.2.0,$1)
   if echo "$tmp" | grep ':' >/dev/null 2>/dev/null ; then
      req_libgcrypt_api=`echo "$tmp"     | sed 's/\(.*\):\(.*\)/\1/'`
@@ -59,7 +60,7 @@ AC_DEFUN([AM_PATH_LIBGCRYPT],
                sed 's/\([[0-9]]*\)\.\([[0-9]]*\)\.\([[0-9]]*\).*/\3/'`
     if test "$major" -gt "$req_major"; then
         ok=yes
-    else 
+    else
         if test "$major" -eq "$req_major"; then
             if test "$minor" -gt "$req_minor"; then
                ok=yes
@@ -98,6 +99,19 @@ AC_DEFUN([AM_PATH_LIBGCRYPT],
     LIBGCRYPT_CFLAGS=`$LIBGCRYPT_CONFIG --cflags`
     LIBGCRYPT_LIBS=`$LIBGCRYPT_CONFIG --libs`
     ifelse([$2], , :, [$2])
+    libgcrypt_config_host=`$LIBGCRYPT_CONFIG --host 2>/dev/null || echo none`
+    if test x"$libgcrypt_config_host" != xnone ; then
+      if test x"$libgcrypt_config_host" != x"$host" ; then
+  AC_MSG_WARN([[
+***
+*** The config script $LIBGCRYPT_CONFIG was
+*** built for $libgcrypt_config_host and thus may not match the
+*** used host $host.
+*** You may want to use the configure option --with-libgcrypt-prefix
+*** to specify a matching config script.
+***]])
+      fi
+    fi
   else
     LIBGCRYPT_CFLAGS=""
     LIBGCRYPT_LIBS=""