configure.ac: used more reliable method to detect host architecture on Solaris,

really use generated PKG_CONFIG_PATH

configure.ac

@@ -1405,7 +1405,22 @@ AS_IF([test "x$with_gnutls" != "xno" && test "x$have_gnutls" != "xyes"],
      [
       AS_IF([[test "x$host_os" = "xsolaris2.11" && test "x$cross_compiling" = "xno"]],
        [
-        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[char size_chk[sizeof(char*)-7];]], [[]])],
+        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+char size_chk[7-sizeof(char*)];
+#if defined(_LP64) || defined(__LP64__) || defined(__x86_64) || defined(__x86_64__)
+#error This is 64-bit target.
+choke me now
+#endif
+#if defined(__amd64) || defined(__amd64__) || defined(__sparcv9) || defined(__sparc_v9__)
+#error This is 64-bit target.
+choke me now
+#endif
+           ]], [[]]
+          )
+         ],
+         [
+          mhd_cv_pkgconf_add_dirs='/usr/lib/pkgconfig/gnutls-3'
+         ],
          [
           AS_IF([[test "x$host_cpu" = "xx86_64" || test "x$host_cpu" = "xi386"]],
                   [[mhd_cv_pkgconf_add_dirs='/usr/lib/amd64/pkgconfig/gnutls-3:/usr/lib/amd64/pkgconfig']],
@@ -1413,9 +1428,6 @@ AS_IF([test "x$with_gnutls" != "xno" && test "x$have_gnutls" != "xyes"],
                   [[mhd_cv_pkgconf_add_dirs='/usr/lib/sparkv9/pkgconfig/gnutls-3:/usr/lib/sparkv9/pkgconfig']],
                   [[mhd_cv_pkgconf_add_dirs='/usr/lib/64/pkgconfig/gnutls-3:/usr/lib/64/pkgconfig']]
           )
-         ],
-         [
-          mhd_cv_pkgconf_add_dirs='/usr/lib/pkgconfig/gnutls-3'
          ]
         )
        ],
@@ -1427,6 +1439,7 @@ AS_IF([test "x$with_gnutls" != "xno" && test "x$have_gnutls" != "xyes"],
      [
       test "x$PKG_CONFIG_PATH" = "x" || PKG_CONFIG_PATH="${PKG_CONFIG_PATH}${PATH_SEPARATOR}"
       PKG_CONFIG_PATH="${PKG_CONFIG_PATH}${mhd_cv_pkgconf_add_dirs}"
+      export PKG_CONFIG_PATH
      ]
     )
     PKG_CHECK_MODULES(GNUTLS, [[gnutls]],