Support "Solaris 10 using recent Sun Studio".

Patch from Monty Taylor <monty.taylor@gmail.com>.

CHANGES.txt

@@ -41,6 +41,7 @@
   * Simplify template usage to work with MSVC 2003.
   * Work around GCC 4.3.x x86_64 compiler bug that caused crashes on startup.
     (This affected Fedora 9 in particular.)
+  * Now works on "Solaris 10 using recent Sun Studio".
 
   Java
   * New overload of mergeFrom() which parses a slice of a byte array instead

CONTRIBUTORS.txt

@@ -51,3 +51,5 @@ Non-Google patch contributors:
     * Added @Override annotation to generated Java code where appropriate.
   Vincent Choinière <Choiniere.Vincent@hydro.qc.ca>
     * Tru64 support.
+  Monty Taylor <monty.taylor@gmail.com>
+    * Solaris 10 + Sun Studio fix.

configure.ac

@@ -12,13 +12,22 @@ AC_INIT([protobuf],[2.0.3-SNAPSHOT],[protobuf@googlegroups.com])
 
 AC_CONFIG_SRCDIR(src/google/protobuf/message.cc)
 AC_CONFIG_HEADERS([config.h])
+AC_CONFIG_MACRO_DIR([m4])
 AM_INIT_AUTOMAKE
 
 # Checks for programs.
 AC_PROG_CC
 AC_PROG_CXX
+ACX_USE_SYSTEM_EXTENSIONS
 AC_PROG_LIBTOOL
 AM_CONDITIONAL(GCC, test "$GCC" = yes)   # let the Makefile know if we're gcc
+AC_CHECK_DECL([__SUNPRO_C], [SUNCC="yes"], [SUNCC="no"])
+
+AS_IF([test "$SUNCC" = "yes"],[
+  CFLAGS="$CFLAGS -xO4 -xlibmil -xdepend -Xa -mt -xstrconst -D_FORTEC_"
+  CXXFLAGS="$CXXFLAGS -xO4 -xlibmil -mt -D_FORTEC_ -xlang=c99 -compat=5 -library=stlport4 -template=no%extdef"
+])
+
 
 # Checks for header files.
 AC_HEADER_STDC

m4/ac_system_extensions.m4

@@ -0,0 +1,37 @@
+dnl Provide AC_USE_SYSTEM_EXTENSIONS for old autoconf machines.
+AC_DEFUN([ACX_USE_SYSTEM_EXTENSIONS],[
+  ifdef([AC_USE_SYSTEM_EXTENSIONS],[
+    AC_USE_SYSTEM_EXTENSIONS
+  ],[
+    AC_BEFORE([$0], [AC_COMPILE_IFELSE])
+    AC_BEFORE([$0], [AC_RUN_IFELSE])
+
+    AC_REQUIRE([AC_GNU_SOURCE])
+    AC_REQUIRE([AC_AIX])
+    AC_REQUIRE([AC_MINIX])
+
+    AH_VERBATIM([__EXTENSIONS__],
+[/* Enable extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# undef _POSIX_PTHREAD_SEMANTICS
+#endif
+#ifndef _TANDEM_SOURCE
+# undef _TANDEM_SOURCE
+#endif])
+    AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
+      [ac_cv_safe_to_define___extensions__],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([
+#           define __EXTENSIONS__ 1
+            AC_INCLUDES_DEFAULT])],
+         [ac_cv_safe_to_define___extensions__=yes],
+         [ac_cv_safe_to_define___extensions__=no])])
+    test $ac_cv_safe_to_define___extensions__ = yes &&
+      AC_DEFINE([__EXTENSIONS__])
+    AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
+    AC_DEFINE([_TANDEM_SOURCE])
+  ])
+])

src/google/protobuf/stubs/strutil.cc

@@ -35,6 +35,7 @@
 #include <float.h>    // FLT_DIG and DBL_DIG
 #include <limits>
 #include <limits.h>
+#include <stdio.h>
 
 #ifdef _WIN32
 // MSVC has only _snprintf, not snprintf.

src/google/protobuf/stubs/strutil_unittest.cc

@@ -34,6 +34,7 @@
 
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
+#include <locale.h>
 
 namespace google {
 namespace protobuf {

src/gtest/gtest.cc

@@ -40,6 +40,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <wchar.h>
 
 #ifdef GTEST_OS_LINUX