spawn-posix.c:345:5: error: use of undeclared identifier 'environ'

Index: src/spawn-posix.c
--- src/spawn-posix.c.orig
+++ src/spawn-posix.c
@@ -55,6 +55,10 @@
 # include <dirent.h>
 #endif /*__linux__ */
 
+#ifdef __OpenBSD__
+extern char** environ;
+#endif
+
 #include "gpgrt-int.h"
 
 
