cmake: Enable POSIX fsops code for PS2 and PSP.

CMakeLists.txt

@@ -2672,7 +2672,9 @@ elseif(PSP)
   sdl_glob_sources("${SDL3_SOURCE_DIR}/src/filesystem/psp/*.c")
   set(HAVE_SDL_FILESYSTEM TRUE)
 
-  # !!! FIXME: do we need a FSops implementation for this?
+  set(SDL_FSOPS_POSIX 1)
+  sdl_sources("${SDL3_SOURCE_DIR}/src/filesystem/posix/SDL_sysfsops.c")
+  set(HAVE_SDL_FSOPS TRUE)
 
   if(SDL_JOYSTICK)
     set(SDL_JOYSTICK_PSP 1)
@@ -2745,7 +2747,9 @@ elseif(PS2)
   sdl_glob_sources("${SDL3_SOURCE_DIR}/src/filesystem/ps2/*.c")
   set(HAVE_SDL_FILESYSTEM TRUE)
 
-  # !!! FIXME: do we need a FSops implementation for this?
+  set(SDL_FSOPS_POSIX 1)
+  sdl_sources("${SDL3_SOURCE_DIR}/src/filesystem/posix/SDL_sysfsops.c")
+  set(HAVE_SDL_FSOPS TRUE)
 
   if(SDL_JOYSTICK)
     set(SDL_JOYSTICK_PS2 1)