diff --git a/mailx.spec b/mailx.spec
index 73866a4..e5d8b25 100644
--- a/mailx.spec
+++ b/mailx.spec
@@ -23,6 +23,7 @@ BuildRequires:  man
 BuildRequires:  openssl-devel
 BuildRequires:  pcre
 BuildRequires:  postfix
+BuildRequires:  pkgconfig(openssl)
 Url:            http://heirloom.sourceforge.net/mailx.html
 Provides:       mail
 Recommends:     smtp_daemon