Updated platform specifier

CMakeLists.txt

@@ -5,7 +5,7 @@ project(libnut)
 
 # Source
 set(SOURCE_FILES "src/libnut.cc" "src/deadbeef_rand.c" "src/mouse.c" "src/keypress.c" "src/keycode.c" "src/screen.c" "src/screengrab.c" "src/snprintf.c" "src/MMBitmap.c")
-if (LINUX)
+if (UNIX AND NOT APPLE)
     set(SOURCE_FILES "${SOURCE_FILES}" "src/xdisplay.c")
 endif()
 add_library(${PROJECT_NAME} SHARED ${SOURCE_FILES})
@@ -17,15 +17,15 @@ set(LIBS "")
 set(INCLUDES "")
 
 # External libs
-if (APPLE)
+if (UNIX AND APPLE)
     message(STATUS "macOS build")
     set(LIBS "${LIBS}" "-framework ApplicationServices")
     set(LIBS "${LIBS}" "-framework Carbon")
     set(LIBS "${LIBS}" "-framework CoreFoundation")
     set(LIBS "${LIBS}" "-framework OpenGL")
 elseif (WIN32)
     message(STATUS "Windows build")
-elseif (LINUX)
+elseif (UNIX AND NOT APPLE)
     message(STATUS "Linux build")
     set(LIBS "${LIBS}" "-lpng")
     set(LIBS "${LIBS}" "-lz")