[build] switch to -std=gnu++0x

This allows removal of M_PI hack while being supported by both gcc and
clang.

Author: AMDmi3

CMakeLists.txt

@@ -64,7 +64,7 @@ ENDIF(EXISTS "${PROJECT_SOURCE_DIR}/gmock" AND IS_DIRECTORY "${PROJECT_SOURCE_DI
 
 include_directories(include ${Boost_INCLUDE_DIRS} ${LOG4CPP_INCLUDE_DIRS} ${SigC++_INCLUDE_DIRS} ${Freetype_INCLUDE_DIRS} ${Cairomm_INCLUDE_DIRS})
 
-ADD_DEFINITIONS("-std=c++0x")
+ADD_DEFINITIONS("-std=gnu++0x") # gnu is required for e.g. M_PI to be defined
 ADD_DEFINITIONS(-DBOOST_TEST_DYN_LINK)
 ADD_DEFINITIONS(${LOG4CPP_DEFINITIONS})
 ADD_DEFINITIONS(-DStatistic_Activated)

include/settings.hpp

@@ -57,11 +57,6 @@
 #include <log4cpp/Priority.hh>
 #include <log4cpp/Category.hh>
 
-// M_PI fix
-#ifndef M_PI
-#define M_PI           3.14159265358979323846
-#endif
-
 #ifdef ALACARTE_TEST
 	#define TESTABLE virtual
 #else