Fix bug with cmake and old version of GCC
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1f556f3..607b2c4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,7 +21,14 @@
string(REGEX MATCH "Clang" CMAKE_COMPILER_IS_CLANG "${CMAKE_C_COMPILER_ID}")
if(CMAKE_COMPILER_IS_GNUCC)
- set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -W -Wdeclaration-after-statement -Wwrite-strings -Wlogical-op")
+ # some warnings we want are not available with old GCC versions
+ # note: starting with CMake 2.8 we could use CMAKE_C_COMPILER_VERSION
+ execute_process(COMMAND ${CMAKE_C_COMPILER} -dumpversion
+ OUTPUT_VARIABLE GCC_VERSION)
+ set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -W -Wdeclaration-after-statement -Wwrite-strings")
+ if (GCC_VERSION VERSION_GREATER 4.5 OR GCC_VERSION VERSION_EQUAL 4.5)
+ set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wlogical-op")
+ endif()
set(CMAKE_C_FLAGS_RELEASE "-O2")
set(CMAKE_C_FLAGS_DEBUG "-O0 -g3")
set(CMAKE_C_FLAGS_COVERAGE "-O0 -g3 --coverage")