Resolve CI failure with MinGW

src/CMakeLists.txt

@@ -188,10 +188,12 @@ if(SHARED)
       PUBLIC ${GRAPHICS}
   )
 
-  target_compile_definitions(raylib
+  if(MSVC)
+    target_compile_definitions(raylib
       PRIVATE $<BUILD_INTERFACE:BUILD_LIBTYPE_SHARED>
       INTERFACE $<INSTALL_INTERFACE:USE_LIBTYPE_SHARED>
-  )
+    )
+  endif()
 
   set(PKG_CONFIG_LIBS_EXTRA "")