Enable colored diagnostics in ninja builds when building with gcc 4.9+.

GCC has supported -fdiagnostics-color since 4.9.

https://reviews.llvm.org/D47083

llvm-svn: 332793
diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index 7687a46..676f156 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -720,11 +720,13 @@
 add_definitions( -D__STDC_FORMAT_MACROS )
 add_definitions( -D__STDC_LIMIT_MACROS )
 
-# clang doesn't print colored diagnostics when invoked from Ninja
+# clang and gcc don't default-print colored diagnostics when invoked from Ninja.
 if (UNIX AND
-    CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND
-    CMAKE_GENERATOR STREQUAL "Ninja")
-  append("-fcolor-diagnostics" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
+    CMAKE_GENERATOR STREQUAL "Ninja" AND
+    (CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR
+     (CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND
+      NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.9))))
+  append("-fdiagnostics-color" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
 endif()
 
 # lld doesn't print colored diagnostics when invoked from Ninja