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/dthelp/dthelpprint/dthelpprint.msg

@@ -44,11 +44,11 @@ $quote "
 
 $set 2
 $ *****  Module: PrintUtil.c *****
-$
+$ 
 
 $set 3
 $ *****  Module: PrintTopics.c *****
-$
+$ 
 $ ** LOCALIZE THESE MESSAGES **
 1 "%s Error: helpType is topic, but no helpVolume specified.\n"
 2 "%s Error: unable to locate help volume %s\n"
@@ -72,7 +72,7 @@ $ string used by can't get a topic title associated with an index subentry
 
 $set 4
 $ *****  Module: PrintManStrFile.c *****
-$
+$ 
 $ ** LOCALIZE THESE MESSAGES **
 1 "%s Error: helpType is string, but no stringData specified.\n"
 2 "%s Error: helpType is dynamic string, but no stringData specified.\n"
@@ -82,7 +82,7 @@ $ ** LOCALIZE THESE MESSAGES **
 
 $set 5
 $ *****  Module: Initialize.c *****
-$
+$ 
 $ ** LOCALIZE THESE MESSAGES **
 $ Messages 1 to 29: dthelpprint usage message
 $ **DO NOT LOCALIZE** the command line option names (e.g. -copies).
@@ -130,7 +130,7 @@ $ arg order: directory prefix processid filecnt suffix
 
 $set 6
 $ *****  Module: Main.c *****
-$
+$ 
 $ ** LOCALIZE THESE MESSAGES **
 1 "%s Error: Illegal helpType %d.\n"