message catalogs: fix comment lines, also remove linux hack in merge.c

According to the spec, blank lines in message catalogs or lines
beginning with '$ ' are valid comments.

However, there were many cases where lines in the message catalogs
contained just a single '$', without the required space after it.

Under linux, this caused 126766 error lines (in my builds) of the
form:

... unknown directive `': line ignored

This also causes gencat to exit with a non-0 exit code.  Even though
gencat says it ignores the line, it really doesn't.

An early porting change to programs/localized/util/merge.c was made to
ignore this return value on linux.  This hack has now been removed.

Build logs are a lot smaller and cleaner now.

cde/programs/localized/C/config/sys.font.tmsg

@@ -25,12 +25,12 @@ $ *                         \t                  horizontal tab
 $ *                         \ (at end of line)  continue on same line
 $ *
 $ *****************************************************************************
-$
+$ 
 $ ----------------------------------------------------------------------------
 $ Do not translate message 1 - 7.
 $ These are not messages, but locale dependent values.
 $ ----------------------------------------------------------------------------
-$
+$ 
 $ *FontList
 1 -dt-interface system-medium-r-normal-m*-*-*-*-*-*-*-*-*:
 $ *XmText*FontList