diff --git a/src/header/sys_mman/cbindgen.toml b/src/header/sys_mman/cbindgen.toml
index fe41be83cf..72405bf5ab 100644
--- a/src/header/sys_mman/cbindgen.toml
+++ b/src/header/sys_mman/cbindgen.toml
@@ -1,6 +1,9 @@
 sys_includes = ["stdarg.h", "stdint.h", "sys/types.h"]
-include_guard = "_SYS_MMAN_H"
-trailer = "#define MAP_FAILED ((void *) -1)"
+include_guard = "_RELIBC_SYS_MMAN_H"
+after_includes = """
+
+#define MAP_FAILED ((void *) -1)
+"""
 language = "C"
 style = "Tag"
 no_includes = true