fixing configure.ac to prepare compilation of libtalerutil_wallet under emscripten

configure.ac

@@ -49,6 +49,14 @@ AC_ARG_ENABLE([wallet],
 AC_MSG_RESULT($wallet_only)
 AM_CONDITIONAL([WALLET_ONLY], [test "x$wallet_only" = "xyes"])
 
+
+# Require minimum libgcrypt version
+need_libgcrypt_version=1.6.1
+AC_DEFINE_UNQUOTED([NEED_LIBGCRYPT_VERSION], ["$need_libgcrypt_version"],
+                                             [minimum version of libgcrypt required])
+AM_PATH_LIBGCRYPT([$need_libgcrypt_version])
+
+
 if test "$wallet_only" != yes
 then
 
@@ -79,6 +87,7 @@ AS_IF([test $libgnunetutil != 1],
 ***   https://gnunet.org
 *** ]])])
 
+
 # check for libmicrohttpd
 microhttpd=0
 AC_MSG_CHECKING([for microhttpd])
@@ -127,6 +136,15 @@ AS_IF([test $jansson = 0],
 else
 
 # Check for GNUnet's libgnunetutil_taler_wallet.
+
+CFLAGS_SAVE=$CFLAGS
+LDFLAGS_SAVE=$LDFLAGS
+CFLAGS="$CFLAGS $LIBGCRYPT_CFLAGS"
+LDFLAGS="$LDFLAGS $LIBGCRYPT_LDFLAGS"
+LIBS_SAVE="$LIBS"
+LIBS="-lgcrypt -lgpg-error $LIBS"
+
+
 libgnunetutil_taler_wallet=0
 AC_MSG_CHECKING([for libgnunetutil_taler_wallet])
 AC_ARG_WITH(gnunet,
@@ -140,7 +158,7 @@ AS_CASE([$with_gnunet],
         [LDFLAGS="-L$with_gnunet/lib $LDFLAGS"
          CPPFLAGS="-I$with_gnunet/include $CPPFLAGS"])
 AC_CHECK_HEADERS([gnunet/platform.h gnunet/gnunet_util_taler_wallet_lib.h],
- [AC_CHECK_LIB([gnunetutil_taler_wallet], [GNUNET_CRYPTO_hash], libgnunetutil_taler_wallet=1)],
+ [AC_CHECK_LIB([gnunetutil_taler_wallet], [GNUNET_CRYPTO_hash_context_start], libgnunetutil_taler_wallet=1)],
   [], [#ifdef HAVE_GNUNET_PLATFORM_H
         #include <gnunet/platform.h>
        #endif])
@@ -153,6 +171,11 @@ AS_IF([test $libgnunetutil_taler_wallet != 1],
 *** Run GNUnet's configure with --enable-taler-wallet as well!
 *** ]])])
 
+CFLAGS=$CFLAGS_SAVE
+LDFLAGS=$LDFLAGS_SAVE
+LIBS=$LIBS_SAVE
+
+
 fi
 
 TALER_LIB_LDFLAGS="-export-dynamic -no-undefined"
@@ -217,12 +240,6 @@ then
 fi
 
 
-# Require minimum libgcrypt version
-need_libgcrypt_version=1.6.1
-AC_DEFINE_UNQUOTED([NEED_LIBGCRYPT_VERSION], ["$need_libgcrypt_version"],
-                                             [minimum version of libgcrypt required])
-AM_PATH_LIBGCRYPT([$need_libgcrypt_version])
-
 # should developer logic be compiled (not-for-production code)?
 AC_MSG_CHECKING(whether to compile developer logic)
 AC_ARG_ENABLE([developer-mode],