BUG: fix for bug 6172 add get source file prop LANGUAGE

Source/cmGetSourceFilePropertyCommand.cxx

@@ -49,6 +49,11 @@ bool cmGetSourceFilePropertyCommand::InitialPass(
       // needs to be changed to be mutable etc. for computed properties to
       // work properly.
       sf->GetFullPath();
+      } 
+    else if(args[2] == "LANGUAGE")
+      {
+      this->Makefile->AddDefinition(var, sf->GetLanguage());
+      return true;
       }
     const char *prop = sf->GetProperty(args[2].c_str());
     if (prop)

Tests/COnly/CMakeLists.txt

@@ -12,3 +12,9 @@ if(MSVC_VERSION)
 endif(MSVC_VERSION)
 string(ASCII 35 32 67 77 97 107 101 ASCII_STRING)
 message(STATUS "String: ${ASCII_STRING}")
+get_source_file_property(LANG conly.c LANGUAGE)
+if("${LANG}" STREQUAL "C")
+  message("Language is C")
+else("${LANG}" STREQUAL "C")
+  message(FATAL_ERROR "Bad language for file conly.c")
+endif("${LANG}" STREQUAL "C")