diff --git a/src/basic/basic-forward.h b/src/basic/basic-forward.h
index 38c3098f32..dae8788140 100644
--- a/src/basic/basic-forward.h
+++ b/src/basic/basic-forward.h
@@ -117,7 +117,12 @@ typedef struct SocketAddress SocketAddress;
 /* We duplicate various commonly used constants here so we can keep most static inline functions without
  * having to include the full header that provides these constants. */
 
+/* glibc defines AT_FDCWD as -100, but musl defines it as (-100). */
+#ifdef __GLIBC__
 #define AT_FDCWD                -100
+#else
+#define AT_FDCWD                (-100)
+#endif
 #define AT_EMPTY_PATH           0x1000
 #define AT_SYMLINK_FOLLOW       0x400
 #define AT_SYMLINK_NOFOLLOW     0x100