diff --git a/res/res_http_post.c b/res/res_http_post.c
index dea242c36b..0a7200bc32 100644
--- a/res/res_http_post.c
+++ b/res/res_http_post.c
@@ -38,7 +38,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <gmime/gmime.h>
-#if defined (__OpenBSD__) || defined(__FreeBSD__) || defined(__DragonFly__) || defined(__NetBSD__) || defined(__Darwin__)
+#if defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__DragonFly__) || defined(__NetBSD__) || defined(__Darwin__) || defined(SOLARIS)
 #include <libgen.h>
 #endif