diff --git a/.clangd b/.clangd
index 6f7b3be..608f94b 100644
--- a/.clangd
+++ b/.clangd
@@ -1,2 +1,2 @@
 CompileFlags:
-  Add: ["-std=c23", "-x", "c"]
+  Add: ["-std=c23", "-x", "c", "-D_POSIX_C_SOURCE=200809L"]