CMake: Add -std=c++11 to build (#300)

* CI: Add -std=c++11 to macos build

Trying to fix macos build broken by
#240

* CMakeLists.txt: Add -std=c++11 to build

CMakeLists.txt

@@ -10,6 +10,14 @@ ENDIF()
 
 PROJECT( MegaGlest )
 
+# This helps prevent certain errors such as what's mentioned in
+# https://github.com/MegaGlest/megaglest-source/pull/300
+# and also some consider it good practice to specify a standard
+#
+# https://cmake.org/cmake/help/v3.7/prop_tgt/CXX_STANDARD.html?highlight=cxx_standard
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
 #SET(CMAKE_VERBOSE_MAKEFILE ON)
 
 #

mk/macos/CMakeLists.txt

@@ -8,10 +8,6 @@
 # Seems like a good place to add version specific compiler flags too.
 
 IF(NOT CONFIG_HAS_BEEN_RUN_BEFORE)
-	IF ("${CMAKE_CXX_COMPILER_ID}" MATCHES "(Apple)?Clang")
-		SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -stdlib=libc++")
-		#SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility-inlines-hidden")
-	ENDIF()
 	SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ftree-vectorize" CACHE STRING "Flags used by the compiler during all build types." FORCE)
 ENDIF()
 

source/g3d_viewer/CMakeLists.txt

@@ -7,16 +7,6 @@ SET(TARGET_NAME_MANPAGE "${TARGET_NAME}.6")
 IF(BUILD_MEGAGLEST_MODEL_VIEWER)
 	MESSAGE(STATUS "Will try to build MegaGlest model viewer")
 
-	IF(UNIX AND "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" AND NOT "${CMAKE_SYSTEM_NAME}" STREQUAL "Linux")
-		IF("${CMAKE_CXX_COMPILER_VERSION}" VERSION_LESS 4.7 OR NOT "${CMAKE_CXX_COMPILER_VERSION}")
-			ADD_DEFINITIONS("-std=gnu++0x")
-		ELSEIF("${CMAKE_CXX_COMPILER_VERSION}" VERSION_LESS 5.1)
-			ADD_DEFINITIONS("-std=c++11")
-		ENDIF()
-
-		# Was required at least on bsd and macos.
-	ENDIF()
-
 	IF(NOT VCPKG_TARGET_TRIPLET)
 		FIND_PACKAGE(${SDL_VERSION_NAME} REQUIRED)
 	ELSE()

source/glest_map_editor/CMakeLists.txt

@@ -7,16 +7,6 @@ SET(TARGET_NAME_MANPAGE "${TARGET_NAME}.6")
 IF(BUILD_MEGAGLEST_MAP_EDITOR)
 	MESSAGE(STATUS "Will try to build MegaGlest map editor")
 
-	IF(UNIX AND "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" AND NOT "${CMAKE_SYSTEM_NAME}" STREQUAL "Linux")
-		IF("${CMAKE_CXX_COMPILER_VERSION}" VERSION_LESS 4.7 OR NOT "${CMAKE_CXX_COMPILER_VERSION}")
-			ADD_DEFINITIONS("-std=gnu++0x")
-		ELSEIF("${CMAKE_CXX_COMPILER_VERSION}" VERSION_LESS 5.1)
-			ADD_DEFINITIONS("-std=c++11")
-		ENDIF()
-
-		# Was required at least on bsd and macos.
-	ENDIF()
-
 	IF(NOT VCPKG_TARGET_TRIPLET)
 		FIND_PACKAGE(${SDL_VERSION_NAME} REQUIRED)
 	ELSE()