GB, GBA: Fix crashes when attempting to identify null VFiles

CHANGES

@@ -17,6 +17,7 @@ Bugfixes:
  - GB Core: Fix palette loading when loading a foreign config
  - Qt: Fix LOG argument order
  - GB Memory: Prevent accessing empty SRAM (fixes mgba.io/i/831)
+ - GB, GBA: Fix crashes when attempting to identify null VFiles
 Misc:
  - GBA Timer: Use global cycles for timers
  - GBA: Extend oddly-sized ROMs to full address space (fixes mgba.io/i/722)

src/gb/gb.c

@@ -658,6 +658,9 @@ void GBIllegal(struct LR35902Core* cpu) {
 }
 
 bool GBIsROM(struct VFile* vf) {
+	if (!vf) {
+		return false;
+	}
 	vf->seek(vf, 0x104, SEEK_SET);
 	uint8_t header[4];
 

src/gba/gba.c

@@ -527,6 +527,9 @@ bool GBAIsROM(struct VFile* vf) {
 		return isGBA;
 	}
 #endif
+	if (!vf) {
+		return false;
+	}
 	if (vf->seek(vf, GBA_ROM_MAGIC_OFFSET, SEEK_SET) < 0) {
 		return false;
 	}