Harmonize the option processing in 'config' and 'config.com'

The help text for -d in 'config' was aged, and the option processing
in 'config.com' was just different.  This harmonizes 'config.com' with
the instructions in INSTALL and both current reality.

Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/config b/config
index ba66b33..ae349ec 100755
--- a/config
+++ b/config
@@ -33,7 +33,7 @@
 -t*) TEST="true";;
 -h*) TEST="true"; cat <<EOF
 Usage: config [options]
- -d	Add a debug- prefix to machine choice.
+ -d	Build with debugging when possible.
  -t	Test mode, do not run the Configure perl script.
  -h	This help.