diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6917886d33..cc2283f8d0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -26,8 +26,6 @@ if (CCACHE_FOUND)
 	set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK ccache)
 endif()
 
-add_definitions(-DCMAKE_BUILD)
-
 # We use libpng's static library and don't need to build the shared library and run the tests
 set(PNG_SHARED OFF CACHE BOOL "Build shared lib." FORCE)
 set(PNG_TESTS  OFF CACHE BOOL "Build tests." FORCE)