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/app-defaults/Dtstyle.tmsg

@@ -28,30 +28,30 @@ $ *****************************************************************************
 $ ----------------------------------------------------------------------------
 $ Menu Accelerators
 $ ----------------------------------------------------------------------------
-$
+$ 
 $ Message 1 can be translated. These are shown on the menu.
 $ Message 2 should not be changed unless accelerator keys need to
 $ be changed in your language. If you want to change accelerator, it is
 $ recommended not to change modifier keys.
 $ Example; (Change underlined part only)
-$
+$ 
 $  Menu label "Keyword..." --> "Abcdef..."
-$
+$ 
 $  1 Ctrl+K       -->  1 Ctrl+A
 $         -                   -
 $  2 Ctrl<Key>k   -->  2 Ctrl<Key>a
 $             -                   -
-$
+$ 
 $  Message 1, 2. Menu label is "Exit".
-$
+$ 
 1 Alt+F4
 2 Alt<key>F4
-$
+$ 
 $ ----------------------------------------------------------------------------
 $ Do not translate message 3 - 5.
 $ These are not messages, but locale dependent values.
 $ ----------------------------------------------------------------------------
-$
+$ 
 $ NumFonts
 3 7
 $ Set of SystemFont