cmake: fix linking to libssp and linking bin2c

Only add the macro `-D_FORTIFY_SOURCE=2` if we are linking to libssp
with gcc, do not use it at all on clang.

For `HostCompile.cmake` add the macro `-Dmain=main` to redefine the
macro added by SDL2 to compile flags `-Dmain=SDL_main`.

Fix #548.

Signed-off-by: Rafael Kitover <rkitover@gmail.com>

CMakeLists.txt

@@ -507,8 +507,17 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID STREQUAL Clang)
     # common flags
     set(MY_C_FLAGS -pipe -Wformat -Wformat-security -feliminate-unused-debug-types)
 
-    if(NOT CMAKE_BUILD_TYPE MATCHES Debug)
-        list(APPEND MY_C_FLAGS -D_FORTIFY_SOURCE=2)
+    if(ENABLE_SSP AND CMAKE_BUILD_TYPE STREQUAL Debug)
+        if(WIN32)
+            set(SSP_STATIC ON)
+        endif()
+
+        find_package(SSP)
+
+        if(SSP_LIBRARY)
+            list(APPEND MY_C_FLAGS        -D_FORTIFY_SOURCE=2)
+            list(APPEND MY_C_LINKER_FLAGS ${SSP_LIBRARY})
+        endif()
     endif()
 
     if(NOT (WIN32 OR X86_32)) # inline asm is not allowed with -fPIC
@@ -603,18 +612,6 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID STREQUAL Clang)
             include(UseGCCBinUtilsWrappers)
         endif()
 
-        if(WIN32)
-            set(SSP_STATIC ON)
-        endif()
-
-        if(ENABLE_SSP)
-            find_package(SSP)
-
-            if(SSP_LIBRARY)
-                set(MY_C_LINKER_FLAGS ${MY_C_LINKER_FLAGS} ${SSP_LIBRARY})
-            endif()
-        endif()
-
         set(MY_C_LINKER_FLAGS ${MY_C_LINKER_FLAGS} -Wl,-allow-multiple-definition)
 
         if(CMAKE_PREFIX_PATH)

cmake/HostCompile.cmake

@@ -9,17 +9,21 @@ function(host_compile src dst_cmd)
                 set(link_flags -Wl,--subsystem,console)
             endif()
         else()
-            set(dst "${dst_cmd}")
+            set(dst ${dst_cmd})
         endif()
 
         # assume cc foo.c -o foo # will work on most hosts
         add_custom_command(
-            OUTPUT "${dst}"
+            OUTPUT ${dst}
             COMMAND cc ${src} -o ${dst} ${link_flags}
-            DEPENDS "${src}"
+            DEPENDS ${src}
         )
     else()
-        get_filename_component(dst "${dst_cmd}" NAME)
-        add_executable("${dst}" "${src}")
+        get_filename_component(dst ${dst_cmd} NAME)
+
+        add_executable(${dst} ${src})
+
+        # this is necessary because we override main with SDL_main
+        target_compile_definitions(${dst} PRIVATE -Dmain=main)
     endif()
 endfunction()