$NetBSD: patch-Modules_Platform_SunOS.cmake,v 1.3 2012/11/15 19:31:55 adam Exp $

Don't use gcc to link c++ libraries on SunOS,
unless we are really using a gcc lacking libstdc++.

See http://public.kitware.com/pipermail/cmake/2011-July/045300.html

--- Modules/Platform/SunOS.cmake.orig	2012-11-14 19:47:33.000000000 +0000
+++ Modules/Platform/SunOS.cmake
@@ -7,12 +7,20 @@ if(CMAKE_SYSTEM MATCHES "SunOS-4.*")
    set(CMAKE_SHARED_LIBRARY_RUNTIME_C_FLAG_SEP ":")
 endif()
 
+# Take the default c++ shared library creation rule from the
+# CMakeDefaultMakeRuleVariables.cmake file unless using GCC and libstdc++.so
+# does not exist, in which case fall back to the old implementation;
+# using gcc to invoke the linker.
 if(CMAKE_COMPILER_IS_GNUCXX)
   if(CMAKE_COMPILER_IS_GNUCC)
-    set(CMAKE_CXX_CREATE_SHARED_LIBRARY
-        "<CMAKE_C_COMPILER> <CMAKE_SHARED_LIBRARY_CXX_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS>  <SONAME_FLAG><TARGET_SONAME> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
-  else()
-    # Take default rule from CMakeDefaultMakeRuleVariables.cmake.
+    execute_process(
+      COMMAND ${CMAKE_CXX_COMPILER} -print-file-name=libstdc++.so
+      OUTPUT_VARIABLE SHARED_LIBSTDCXX_FILENAME
+      OUTPUT_STRIP_TRAILING_WHITESPACE)
+    if(NOT EXISTS "${SHARED_LIBSTDCXX_FILENAME}")
+      set(CMAKE_CXX_CREATE_SHARED_LIBRARY
+          "<CMAKE_C_COMPILER> <CMAKE_SHARED_LIBRARY_CXX_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS>  <CMAKE_SHARED_LIBRARY_SONAME_CXX_FLAG><TARGET_SONAME> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
+    endif()
   endif()
 endif()
 include(Platform/UnixPaths)