feat: add include guard

3 files changed, 15 insertions, 0 deletions

diff --git a/include/stdarg.h b/include/stdarg.h
index bdc4101..9995ae0 100644
--- a/include/stdarg.h
+++ b/include/stdarg.h
@@ -1,3 +1,6 @@
+#ifndef __DUCC_BUILTIN___STDARG_H__
+#define __DUCC_BUILTIN___STDARG_H__
+
 // System V Application Binary Interface
 // AMD64 Architecture Processor Supplement
 // (With LP64 and ILP32 Programming Models)
@@ -19,3 +22,5 @@ typedef struct __ducc_va_list* va_list;
 
 void va_end(va_list args) {
 }
+
+#endif
diff --git a/include/stddef.h b/include/stddef.h
index d4977de..702d91a 100644
--- a/include/stddef.h
+++ b/include/stddef.h
@@ -1,3 +1,6 @@
+#ifndef __DUCC_BUILTIN___STDDEF_H__
+#define __DUCC_BUILTIN___STDDEF_H__
+
 #define NULL 0
 
 // TODO: unsigned
@@ -8,3 +11,5 @@ typedef long size_t;
 // - nullptr_t (C23)
 // - offsetof
 // - ptrdiff_t
+
+#endif
diff --git a/src/std.h b/src/std.h
index f5dc3ba..a2ab45e 100644
--- a/src/std.h
+++ b/src/std.h
@@ -1,3 +1,6 @@
+#ifndef DUCC_STD_H
+#define DUCC_STD_H
+
 #include <stddef.h>
 
 struct FILE;
@@ -50,3 +53,5 @@ char* dirname(char*);
 #define BOOL int
 #define TRUE 1
 #define FALSE 0
+
+#endif