Qt: Fix sprite/map export file handle leaks (fixs #1141)

src/platform/qt/MapView.cpp

@@ -10,6 +10,7 @@
 #include "LogController.h"
 
 #include <mgba-util/png-io.h>
+#include <mgba-util/vfs.h>
 #ifdef M_CORE_GBA
 #include <mgba/internal/gba/memory.h>
 #endif
@@ -184,5 +185,6 @@ void MapView::exportMap() {
 	QImage map = m_rawMap.rgbSwapped();
 	PNGWritePixelsA(png, map.width(), map.height(), map.bytesPerLine() / 4, static_cast<const void*>(map.constBits()));
 	PNGWriteClose(png, info);
+	vf->close(vf);
 }
 #endif

src/platform/qt/ObjView.cpp

@@ -22,6 +22,7 @@
 #include <mgba/internal/gb/io.h>
 #endif
 #include <mgba-util/png-io.h>
+#include <mgba-util/vfs.h>
 
 using namespace QGBA;
 
@@ -283,6 +284,7 @@ void ObjView::exportObj() {
 	PNGWritePixels8(png, m_objInfo.width * 8, m_objInfo.height * 8, m_objInfo.width * 8, static_cast<void*>(buffer));
 	PNGWriteClose(png, info);
 	delete[] buffer;
+	vf->close(vf);
 }
 #endif