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/sv_SE.ISO8859-1/msg/dtlp.msg

@@ -42,9 +42,9 @@ $ *************************************<L>*************************************
 $quote "
 
 $set 1
-$
+$ 
 $ -- The first group of messages all appear on the Print dialog --
-$
+$ 
 
 
 $  This is the message that appears in the "Printer:" field when no
@@ -89,9 +89,9 @@ $  This is the label on the right button. Pushing this button causes a
 $  help dialog to be posted.
 120 "Hjälp"
 
-$
+$ 
 $ -- The following are error messages. --
-$
+$ 
 
 $  This message is posted when there is a problem with the file specified. 
 $  The file name will be appended to the message. One additional message