c2man: Fix .spec file flag recognition.

tools/c2man.pl

diff --git a/tools/c2man.pl b/tools/c2man.pl
index db9f25f..868e4fc 100755
--- a/tools/c2man.pl
+++ b/tools/c2man.pl
@@ -152,7 +152,7 @@
     {
       $flags |= $FLAG_REGISTER;
     }
-    s/ \-[a-z0-9]+//g;   # Strip flags
+    s/ \-[a-z0-9=_]+//g;   # Strip flags
 
     if( /^(([0-9]+)|@) / )
     {