diff --git a/commit-slab-impl.h b/commit-slab-impl.h
index ac1e6d409a..5c0eb91a5d 100644
--- a/commit-slab-impl.h
+++ b/commit-slab-impl.h
@@ -1,10 +1,10 @@
 #ifndef COMMIT_SLAB_IMPL_H
 #define COMMIT_SLAB_IMPL_H
 
-#define MAYBE_UNUSED __attribute__((__unused__))
+#include "git-compat-util.h"
 
 #define implement_static_commit_slab(slabname, elemtype) \
-	implement_commit_slab(slabname, elemtype, static MAYBE_UNUSED)
+	implement_commit_slab(slabname, elemtype, MAYBE_UNUSED static)
 
 #define implement_shared_commit_slab(slabname, elemtype) \
 	implement_commit_slab(slabname, elemtype, )
diff --git a/git-compat-util.h b/git-compat-util.h
index 95cfcc1aeb..96a3f86d8e 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -412,6 +412,8 @@ static inline char *git_find_last_dir_sep(const char *path)
 #define LAST_ARG_MUST_BE_NULL
 #endif
 
+#define MAYBE_UNUSED __attribute__((__unused__))
+
 #include "compat/bswap.h"
 
 #include "wildmatch.h"
diff --git a/khash.h b/khash.h
index d10caa0c35..532109c87f 100644
--- a/khash.h
+++ b/khash.h
@@ -234,7 +234,7 @@ static const double __ac_HASH_UPPER = 0.77;
 	__KHASH_IMPL(name, SCOPE, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal)
 
 #define KHASH_INIT(name, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
-	KHASH_INIT2(name, static inline, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal)
+	KHASH_INIT2(name, MAYBE_UNUSED static inline, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal)
 
 /* Other convenient macros... */