Make stuff buildable on Mac.

libs/SDL2/CMakeLists.txt

@@ -416,7 +416,7 @@ if(USE_GCC OR USE_CLANG)
   set(CMAKE_REQUIRED_FLAGS "-Wl,--no-undefined")
   check_c_compiler_flag("" HAVE_NO_UNDEFINED)
   set(CMAKE_REQUIRED_FLAGS ${ORIG_CMAKE_REQUIRED_FLAGS})
-  if(HAVE_NO_UNDEFINED)
+  if(HAVE_NO_UNDEFINED AND NOT APPLE) # Flag check produces false positive on (my) Mac.
     list(APPEND EXTRA_LDFLAGS "-Wl,--no-undefined")
   endif()
 endif()

libs/libmodplug-0.8.8.4/src/config.h.cmake

@@ -0,0 +1,13 @@
+#cmakedefine HAVE_SINF
+#cmakedefine HAVE_SETENV
+#cmakedefine HAVE_DLFCN_H
+#cmakedefine HAVE_INTTYPES_H
+#cmakedefine HAVE_MALLOC_H
+#cmakedefine HAVE_MEMORY_H
+#cmakedefine HAVE_STDINT_H
+#cmakedefine HAVE_STDLIB_H
+#cmakedefine HAVE_STRINGS_H
+#cmakedefine HAVE_STRING_H
+#cmakedefine HAVE_SYS_STAT_H
+#cmakedefine HAVE_SYS_TYPES_H
+#cmakedefine HAVE_UNISTD_H

libs/lua-5.1.5/CMakeLists.txt

@@ -46,6 +46,8 @@ endif()
 if (LUA_BUILD_SHARED)
 	add_library(lua51 SHARED ${LUA_SRC})
 	target_include_directories(lua51 PUBLIC src)
-	set_property(TARGET lua51 PROPERTY COMPILE_DEFINITIONS LUA_BUILD_AS_DLL=1)
+	if(MSVC)
+		set_property(TARGET lua51 PROPERTY COMPILE_DEFINITIONS LUA_BUILD_AS_DLL=1)
+	endif()
 	install(TARGETS lua51 RUNTIME DESTINATION . LIBRARY DESTINATION .)
 endif()