Index: b/system/include/libc/locale.h
===================================================================
--- a/system/include/libc/locale.h
+++ b/system/include/libc/locale.h
@@ -7,7 +7,11 @@ extern "C" {
 
 #include <features.h>
 
+#ifdef __cplusplus
 #define NULL 0L
+#else
+#define NULL ((void*)0)
+#endif
 
 #define LC_CTYPE    0
 #define LC_NUMERIC  1
Index: b/system/include/libc/stddef.h
===================================================================
--- a/system/include/libc/stddef.h
+++ b/system/include/libc/stddef.h
@@ -1,7 +1,11 @@
 #ifndef _STDDEF_H
 #define _STDDEF_H
 
+#ifdef __cplusplus
 #define NULL 0L
+#else
+#define NULL ((void*)0)
+#endif
 
 #define __NEED_ptrdiff_t
 #define __NEED_size_t
Index: b/system/include/libc/stdio.h
===================================================================
--- a/system/include/libc/stdio.h
+++ b/system/include/libc/stdio.h
@@ -21,7 +21,11 @@ extern "C" {
 
 #include <bits/alltypes.h>
 
+#ifdef __cplusplus
 #define NULL 0L
+#else
+#define NULL ((void*)0)
+#endif
 
 #undef EOF
 #define EOF (-1)
Index: b/system/include/libc/stdlib.h
===================================================================
--- a/system/include/libc/stdlib.h
+++ b/system/include/libc/stdlib.h
@@ -7,7 +7,11 @@ extern "C" {
 
 #include <features.h>
 
+#ifdef __cplusplus
 #define NULL 0L
+#else
+#define NULL ((void*)0)
+#endif
 
 #define __NEED_size_t
 #define __NEED_wchar_t
Index: b/system/include/libc/string.h
===================================================================
--- a/system/include/libc/string.h
+++ b/system/include/libc/string.h
@@ -7,7 +7,11 @@ extern "C" {
 
 #include <features.h>
 
+#ifdef __cplusplus
 #define NULL 0L
+#else
+#define NULL ((void*)0)
+#endif
 
 #define __NEED_size_t
 #if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
Index: b/system/include/libc/time.h
===================================================================
--- a/system/include/libc/time.h
+++ b/system/include/libc/time.h
@@ -7,7 +7,11 @@ extern "C" {
 
 #include <features.h>
 
+#ifdef __cplusplus
 #define NULL 0L
+#else
+#define NULL ((void*)0)
+#endif
 
 #define __NEED_size_t
 #define __NEED_time_t
Index: b/system/include/libc/unistd.h
===================================================================
--- a/system/include/libc/unistd.h
+++ b/system/include/libc/unistd.h
@@ -15,7 +15,11 @@ extern "C" {
 #define SEEK_CUR 1
 #define SEEK_END 2
 
+#ifdef __cplusplus
 #define NULL 0L
+#else
+#define NULL ((void*)0)
+#endif
 
 #define __NEED_size_t
 #define __NEED_ssize_t
Index: b/system/include/libc/wchar.h
===================================================================
--- a/system/include/libc/wchar.h
+++ b/system/include/libc/wchar.h
@@ -33,7 +33,11 @@ extern "C" {
 #define WCHAR_MIN (-1-0x7fffffff+L'\0')
 #endif
 
+#ifdef __cplusplus
 #define NULL 0L
+#else
+#define NULL ((void*)0)
+#endif
 
 #undef WEOF
 #define WEOF 0xffffffffU