add strp.h to mkdef.pl headers
diff --git a/util/mkdef.pl b/util/mkdef.pl
index 807e80c..46b175d 100755
--- a/util/mkdef.pl
+++ b/util/mkdef.pl
@@ -269,6 +269,7 @@
 my $ssl="ssl/ssl.h";
 $ssl.=" ssl/kssl.h";
 $ssl.=" ssl/tls1.h";
+$ssl.=" ssl/srtp.h";
 
 my $crypto ="crypto/crypto.h";
 $crypto.=" crypto/o_dir.h";