Core: Fix crashes if core directories aren't set

CHANGES

@@ -26,6 +26,7 @@ Other fixes:
  - Core: Improved lockstep driver reliability (Le Hoang Quyen)
  - Switch: Fix threading-related crash on second launch
  - Qt: Fix FPS target maxing out at 59.727 (fixes mgba.io/i/1421)
+ - Core: Fix crashes if core directories aren't set
 Misc:
  - GBA Savedata: EEPROM performance fixes
  - GBA Savedata: Automatically map 1Mbit Flash files as 1Mbit Flash

src/core/core.c

@@ -157,10 +157,16 @@ bool mCorePreloadFile(struct mCore* core, const char* path) {
 }
 
 bool mCoreAutoloadSave(struct mCore* core) {
+	if (!core->dirs.save) {
+		return false;
+	}
 	return core->loadSave(core, mDirectorySetOpenSuffix(&core->dirs, core->dirs.save, ".sav", O_CREAT | O_RDWR));
 }
 
 bool mCoreAutoloadPatch(struct mCore* core) {
+	if (!core->dirs.patch) {
+		return false;
+	}
 	return core->loadPatch(core, mDirectorySetOpenSuffix(&core->dirs, core->dirs.patch, ".ups", O_RDONLY)) ||
 	       core->loadPatch(core, mDirectorySetOpenSuffix(&core->dirs, core->dirs.patch, ".ips", O_RDONLY)) ||
 	       core->loadPatch(core, mDirectorySetOpenSuffix(&core->dirs, core->dirs.patch, ".bps", O_RDONLY));
@@ -217,6 +223,9 @@ bool mCoreLoadState(struct mCore* core, int slot, int flags) {
 }
 
 struct VFile* mCoreGetState(struct mCore* core, int slot, bool write) {
+	if (!core->dirs.state) {
+		return NULL;
+	}
 	char name[PATH_MAX + 14]; // Quash warning
 	snprintf(name, sizeof(name), "%s.ss%i", core->dirs.baseName, slot);
 	return core->dirs.state->openFile(core->dirs.state, name, write ? (O_CREAT | O_TRUNC | O_RDWR) : O_RDONLY);