GBA Memory: Fix copy-on-write memory leak

CHANGES

@@ -37,6 +37,7 @@ Bugfixes:
  - GBA Audio: Increase PSG volume (fixes mgba.io/i/932)
  - 3DS: Fix opening files in directory names with trailing slashes
  - GB MBC: Fix MBC2 saves (fixes mgba.io/i/954)
+ - GBA Memory: Fix copy-on-write memory leak
 Misc:
  - GBA Timer: Use global cycles for timers
  - GBA: Extend oddly-sized ROMs to full address space (fixes mgba.io/i/722)

src/gba/memory.c

@@ -1635,6 +1635,7 @@ void _pristineCow(struct GBA* gba) {
 	}
 	gba->memory.rom = newRom;
 	gba->memory.hw.gpioBase = &((uint16_t*) gba->memory.rom)[GPIO_REG_DATA >> 1];
+	gba->isPristine = false;
 }
 
 void GBAPrintFlush(struct GBA* gba) {