fixed some linker issue

la_5.h

@@ -55,5 +55,6 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#define NANOVG_GL3
 #include "nanovg.h"
 #include "nanovg_gl.h"

lagui-config.cmake

@@ -70,8 +70,8 @@ if (CMAKE_SYSTEM_NAME MATCHES "Linux")
         list(APPEND LAGUI_INCLUDE_DIRS_ALL ${LUA_INCLUDE_DIR})
     endif()
     if(${PNG_FOUND})
-        list(APPEND ${LAGUI_SHARED_LIBS} ${PNG_LIBRARY})
-        list(APPEND ${LAGUI_INCLUDE_DIRS_ALL} ${PNG_INCLUDE_DIR})
+        list(APPEND LAGUI_SHARED_LIBS ${PNG_LIBRARY})
+        list(APPEND LAGUI_INCLUDE_DIRS_ALL ${PNG_INCLUDE_DIR})
     endif()
 elseif (CMAKE_SYSTEM_NAME MATCHES "Windows")
     set(LAGUI_SHARED_LIBS