LibCore: Add mkfifo() syscall wrapper

Author: https://github.com/kennethmyhra
Commit: c10abd6be2
Pull-request: https://github.com/SerenityOS/serenity/pull/11896
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/alimpfard
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/bgianfo ✅
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibCore/System.cpp

@@ -945,4 +945,9 @@ ErrorOr<void> mknod(StringView pathname, mode_t mode, dev_t dev)
 #endif
 }
 
+ErrorOr<void> mkfifo(StringView pathname, mode_t mode)
+{
+    return mknod(pathname, mode | S_IFIFO, 0);
+}
+
 }