diff --git a/Userland/Libraries/LibC/unistd.h b/Userland/Libraries/LibC/unistd.h
index b6e56d9591..a5082dcd03 100644
--- a/Userland/Libraries/LibC/unistd.h
+++ b/Userland/Libraries/LibC/unistd.h
@@ -129,8 +129,17 @@ enum {
     _PC_LINK_MAX
 };
 
+#define _POSIX_FSYNC 200112L
+#define _POSIX_MAPPED_FILES 200112L
+#define _POSIX_MEMORY_PROTECTION 200112L
 #define _POSIX_MONOTONIC_CLOCK 200112L
-#define _POSIX_SAVED_IDS
+#define _POSIX_RAW_SOCKETS 200112L
+#define _POSIX_REGEXP 1
+#define _POSIX_SAVED_IDS 1
+#define _POSIX_SPAWN 200112L
+#define _POSIX_THREADS 200112L
+#define _POSIX_THREAD_ATTR_STACKADDR 200112L
+#define _POSIX_THREAD_ATTR_STACKSIZE 200112L
 #define _POSIX_TIMERS 200809L
 
 /*