From d06a9bdf3ab47231cc91b78dac77bd50de390565 Mon Sep 17 00:00:00 2001
From: Stephen Kelly <steveire@gmail.com>
Date: Sun, 23 Sep 2012 15:02:23 +0200
Subject: [PATCH] Enable some compiler warnings when building CMake.

The warnings are enabled for now only when using GCC 4.2 or later.
It may be possible later to also enable them when building CMake
with clang.  Don't duplicate the compiler flags if already set.
---
 CMakeLists.txt | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ea1c0339e..a67fb6e62 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -585,6 +585,29 @@ option(CMAKE_STRICT
   "Perform strict testing to record property and variable access. Can be used to report any undefined properties or variables" OFF)
 mark_as_advanced(CMAKE_STRICT)
 
+if(NOT CMake_VERSION_IS_RELEASE)
+  if("${CMAKE_C_COMPILER_ID}" STREQUAL "GNU" AND
+      NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS 4.2)
+    set(C_FLAGS_LIST -Wcast-align -Werror-implicit-function-declaration -Wchar-subscripts
+                     -Wall -W -Wpointer-arith -Wwrite-strings -Wformat-security
+                     -Wmissing-format-attribute -fno-common
+    )
+    set(CXX_FLAGS_LIST -Wnon-virtual-dtor -Wcast-align -Wchar-subscripts -Wall -W
+                       -Wshadow -Wpointer-arith -Wformat-security
+    )
+
+    foreach(FLAG_LANG  C CXX)
+      foreach(FLAG ${${FLAG_LANG}_FLAGS_LIST})
+        if(NOT " ${CMAKE_${FLAG_LANG}_FLAGS} " MATCHES " ${FLAG} ")
+          set(CMAKE_${FLAG_LANG}_FLAGS "${CMAKE_${FLAG_LANG}_FLAGS} ${FLAG}")
+        endif()
+      endforeach()
+    endforeach()
+
+    unset(C_FLAGS_LIST)
+    unset(CXX_FLAGS_LIST)
+  endif()
+endif()
 
 # build the remaining subdirectories
 add_subdirectory(Source)