Make sure handles of files opened by W_LoadWadFile are closed if we abort...

Make sure handles of files opened by W_LoadWadFile are closed if we abort loading the files for whatever reason.

ESPECIALLY if the file is already loaded in SRB2, that's just silly.

src/w_wad.c

@@ -381,6 +381,8 @@ UINT16 W_LoadWadFile(const char *filename)
 		if (fread(&header, 1, sizeof header, handle) < sizeof header)
 		{
 			CONS_Alert(CONS_ERROR, M_GetText("Can't read wad header from %s because %s\n"), filename, strerror(ferror(handle)));
+			if (handle)
+				fclose(handle);
 			return INT16_MAX;
 		}
 
@@ -391,6 +393,8 @@ UINT16 W_LoadWadFile(const char *filename)
 			&& memcmp(header.identification, "SDLL", 4) != 0)
 		{
 			CONS_Alert(CONS_ERROR, M_GetText("%s does not have a valid WAD header\n"), filename);
+			if (handle)
+				fclose(handle);
 			return INT16_MAX;
 		}
 
@@ -405,6 +409,8 @@ UINT16 W_LoadWadFile(const char *filename)
 		{
 			CONS_Alert(CONS_ERROR, M_GetText("Wadfile directory in %s is corrupted (%s)\n"), filename, strerror(ferror(handle)));
 			free(fileinfov);
+			if (handle)
+				fclose(handle);
 			return INT16_MAX;
 		}
 
@@ -462,6 +468,8 @@ UINT16 W_LoadWadFile(const char *filename)
 		if (!memcmp(wadfiles[i]->md5sum, md5sum, 16))
 		{
 			CONS_Alert(CONS_ERROR, M_GetText("%s is already loaded\n"), filename);
+			if (handle)
+				fclose(handle);
 			return INT16_MAX;
 		}
 	}