Bug: https://bugs.gentoo.org/887331
--- a/buffer_1.c
+++ b/buffer_1.c
@@ -2,6 +2,6 @@
 #include "buffer.h"
 
 char buffer_1_space[BUFFER_INSIZE];
-static buffer it = BUFFER_INIT(write,1,buffer_1_space,sizeof buffer_1_space);
+static buffer it = BUFFER_INIT((void *)write,1,buffer_1_space,sizeof buffer_1_space);
 buffer *buffer_1 = ⁢
 
--- a/buffer_2.c
+++ b/buffer_2.c
@@ -2,6 +2,6 @@
 #include "buffer.h"
 
 char buffer_2_space[BUFFER_INSIZE];
-static buffer it = BUFFER_INIT(write,2,buffer_2_space,sizeof buffer_2_space);
+static buffer it = BUFFER_INIT((void *)write,2,buffer_2_space,sizeof buffer_2_space);
 buffer *buffer_2 = ⁢
 
--- a/byte.h
+++ b/byte.h
@@ -1,7 +1,9 @@
 #ifndef BYTE_H
 #define BYTE_H
 
-#include <sys/cdefs.h>
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #ifndef __pure__
 #define __pure__
@@ -36,3 +38,6 @@ void byte_zero(void* out, unsigned len);
 #define byte_equal(s,n,t) (!byte_diff((s),(n),(t)))
 
 #endif
+#ifdef __cplusplus
+}
+#endif
--- a/scan.h
+++ b/scan.h
@@ -1,7 +1,9 @@
 #ifndef SCAN_H
 #define SCAN_H
 
-#include <sys/cdefs.h>
+#ifdef __cplusplus
+extern "C" {
+#endif
 #ifndef __pure__
 #define __pure__
 #endif
@@ -59,3 +61,6 @@ extern unsigned int scan_charsetnskip(const char *in,const char *charset,unsigne
 extern unsigned int scan_noncharsetnskip(const char *in,const char *charset,unsigned int limit) __pure__;
 
 #endif
+#ifdef __cplusplus
+}
+#endif
--- a/str.h
+++ b/str.h
@@ -1,7 +1,9 @@
 #ifndef STR_H
 #define STR_H
 
-#include <sys/cdefs.h>
+#ifdef __cplusplus
+extern "C" {
+#endif
 #ifndef __pure__
 #define __pure__
 #endif
@@ -41,3 +43,6 @@ extern int str_start(const char *a,const char *b) __pure__;
 #define str_equal(s,t) (!str_diff((s),(t)))
 
 #endif
+#ifdef __cplusplus
+}
+#endif