1 files changed, 2 insertions, 0 deletions
diff --git a/arena.h b/arena.h
index 89c92d6..1be5cd7 100644
--- a/arena.h
+++ b/arena.h
@@ -69,6 +69,8 @@ void arena_reset(Arena *a) {
 	a->beg = a->start;
 }
 
+#include <stdlib.h>
+
 void *arena_alloc(Arena *a, size_t sz, size_t align) {
 	char *p = a->beg + (-(uintptr_t)a->beg & (align - 1));
 	if (p + sz > a->end) FAIL_WITH_MSG("arena out-of-memory");