diff --git a/m4/ax_pthread.m4 b/m4/ax_pthread.m4
index d09a1cd68..bdb34b0ae 100644
--- a/m4/ax_pthread.m4
+++ b/m4/ax_pthread.m4
@@ -160,11 +160,10 @@ case ${host_os} in
         ;;
 
         darwin*)
-        if test "$CC" = "clang"; then 
-            ax_pthread_flags="$ax_pthread_flags"
-        else 
-            ax_pthread_flags="-pthread $ax_pthread_flags"
-        fi
+        AC_REQUIRE([WOLFSSL_DARWIN_USING_CLANG])
+        AS_IF([test x"$wolfssl_darwin_clang" = x"yes"],
+                [ax_pthread_flags="$ax_pthread_flags"],
+                [ax_pthread_flags="-pthread $ax_pthread_flags"])
         ;;
 esac
 
diff --git a/m4/wolfssl_darwin_clang.m4 b/m4/wolfssl_darwin_clang.m4
new file mode 100644
index 000000000..fee9b6ae0
--- /dev/null
+++ b/m4/wolfssl_darwin_clang.m4
@@ -0,0 +1,37 @@
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   WOLFSSL_DARWIN_USING_CLANG
+#
+# DESCRIPTION
+#
+#   With the advent of Apple Xcode v5.0, the old tool sets are missing from
+#   the distribution. The provided "gcc" executable wrapper accepts the
+#   "-pthread" flag, and passes it to the underlying "clang" which chokes
+#   on it. This script checks the version of the gcc executable to see if
+#   it reports it is really "clang".
+#
+#   The value is placed in the wolfssl_darwin_clang variable.
+#
+# LICENSE
+#
+#   Copyright (c) 2013 John Safranek <john@wolfssl.com>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 1
+
+AC_DEFUN([WOLFSSL_DARWIN_USING_CLANG],
+        [
+            if test x"$CC" = xclang; then
+                wolfssl_darwin_clang=yes
+            elif test x"$CC" = x || test x"$CC" = xgcc; then
+                if /usr/bin/gcc -v 2>&1 | grep 'clang' >/dev/null 2>&1; then
+                    wolfssl_darwin_clang=yes
+                fi
+            fi
+        ])