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/es_ES.ISO8859-1/msg/dtstyle.msg

@@ -679,9 +679,9 @@ $ Messages 13-16 are replacements for messages 5-8
 $set 19
 $ The set 19 contains messages for the I18N dialog
 
-$
+$ 
 $ Messsages 1 to 11 are labels displayed in the dialog.
-$
+$ 
 
 $quote
 
@@ -728,10 +728,10 @@ $ selected element in the preedit Type list (meaning at the next
 $ position).
 11 Mover hacia abajo
 
-$
+$ 
 $ Messages 20-21 are displayed in an warning dialog when the user
 $ hits the OK button.
-$
+$ 
 
 $ Message 20 appears when the user modifies the XmNpreeditType
 $ resource value, and the resource *writeXrdbImmediate is True.
@@ -745,9 +745,9 @@ $ resource value, and the resource *writeXrdbImmediate is False.
 21 La selección entrará en efecto\n\
 en la próxima sesión.
 
-$
+$ 
 $ Messages 30 to 41 appear as errors in Error Dialog.
-$
+$ 
 
 $ Do NOT localize the word HOME.
 30 No se ha definido la variable de entorno HOME.