Wrap subdirectory compilation in conditional

CMakeLists.txt

@@ -15,6 +15,30 @@ add_subdirectory(deps/SDL_ttf EXCLUDE_FROM_ALL)
 
 else()
 
+  find_package(PkgConfig REQUIRED)
+
+  if(NOT TARGET SDL3::SDL3)
+    find_package(SDL3 REQUIRED)
+  endif()
+  if(NOT TARGET SDL3_image::SDL3_image)
+    find_package(SDL3_image REQUIRED)
+  endif()
+  if(NOT TARGET SDL3_mixer::SDL3_mixer)
+    find_package(SDL3_mixer REQUIRED)
+  endif()
+  if(NOT TARGET SDL3_ttf::SDL3_ttf)
+    find_package(SDL3_ttf REQUIRED)
+  endif()
+  if(NOT TARGET akerror::akerror)
+    find_package(akerror REQUIRED)
+  endif()
+  if(NOT TARGET akstdib::akstdlib)
+    find_package(akstdlib REQUIRED)
+  endif()
+  if(NOT TARGET jansson::jansson)
+    find_package(jansson)
+  endif()
+  
 endif()
 
 set(GAMECONTROLLERDB_H "include/akgl/SDL_GameControllerDB.h")