fix gcc15 issues (#10)

* fix some gcc15 issues

* move -std=gnu11

Author: bitten2up

src/game/enemies/drisame.c

@@ -401,4 +401,4 @@ void TaskDestructor_IceBlock(struct Task *t)
     VramFree(iceBlock->s.graphics.dest);
     VramFree(iceBlock->s2.graphics.dest);
     VramFree(iceBlock->s3.graphics.dest);
-}
+}

src/game/multiplayer/mode_select_2.c

@@ -398,4 +398,4 @@ void sub_8010060(void)
         SA2_LABEL(gUnknown_03002280)[0][2] = -1;
         SA2_LABEL(gUnknown_03002280)[0][3] = 0x20;
     }
-}
+}

tools/_shared/arena_alloc/Makefile

@@ -9,7 +9,7 @@ all: libarena_alloc.a
 	@:
 
 %.o: $(SOURCE)
-	$(CC) -O2 $(SOURCE) -static -c $< $(LDFLAGS)
+	$(CC) -O2 -std=gnu11 $(SOURCE) -static -c $< $(LDFLAGS)
 
 libarena_alloc.a: arena_alloc.o
 	$(AR) -rcs $@ $<