diff --git a/config/linux/syscall.h.def b/config/linux/syscall.h.def
index 7f52a26..0daceaf 100644
--- a/config/linux/syscall.h.def
+++ b/config/linux/syscall.h.def
@@ -6,4 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+#ifndef LLVM_LIBC_CONFIG_LINUX_SYSCALL_H
+#define LLVM_LIBC_CONFIG_LINUX_SYSCALL_H
+
 %%include_file(${inline_syscalls})
+
+#endif // LLVM_LIBC_CONFIG_LINUX_SYSCALL_H