Centralize catgets() calls through MsgCat

CDE has relied upon catgets() implementations following a relaxed
interpretation of the XPG internationalization standard that ignored
-1, the standard error value returned by catopen, as the catalog
argument. However, this same behavior causes segmentation faults with
the musl C library.

This patch:

- Centralizes (with the exception of ToolTalk) all calls to catopen(),
  catgets(), and catclose() through MsgCat within the DtSvc library.
- Prevents calls to catgets() and catclose() that rely upon
  undefined behavior.
- Eliminates a number of bespoke catgets() wrappers, including multiple
  redundant caching implementations designed to work around a design
  peculiarity in HP/UX.
- Eases building CDE without XPG internationalization support by providing
  the appropriate macros.

cde/programs/dthelp/dthelpgen/helpgen.c

@@ -24,7 +24,7 @@
 #include <dirent.h>
 #include <errno.h>
 #include <locale.h>
-#include <nl_types.h>
+#include <Dt/MsgCatP.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -226,9 +226,9 @@ GetMessage (
 	   */
 	  nlmsg_fd = (nl_catd) -1;
 	else
-	  nlmsg_fd = catopen(catFileName, NL_CAT_LOCALE);
+	  nlmsg_fd = CATOPEN(catFileName, NL_CAT_LOCALE);
       }
-    msg=catgets(nlmsg_fd,set,n,s);
+    msg=CATGETS(nlmsg_fd,set,n,s);
     return (msg);
 
 }

cde/programs/dthelp/dthelpprint/HelpPrintI.h

@@ -423,7 +423,7 @@ void _DtHPrGetPrOffsetArg(
 char * _DtHPrGetMessage(
         int set,
         int n,
-        char *s);
+        const char *s);
 
 #endif /* DTHELPRPINTP_H */
 

cde/programs/dthelp/dthelpprint/PrintUtil.c

@@ -40,7 +40,7 @@ $COPYRIGHT$:
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <nl_types.h>  /* for message cat processing */
+#include <Dt/MsgCatP.h>  /* for message cat processing */
 #if defined(sun)
 #include <locale.h>
 #else
@@ -245,14 +245,10 @@ $ARGS$:
 char * _DtHPrGetMessage(
         int set,
         int n,
-        char *s)
+        const char *s)
 {       /*$CODE$*/
-   char *msg;
-   char *lang;
-   nl_catd catopen();
-   char *catgets();
    static int s_First = 1;
-   static nl_catd s_Nlmsg_fd;
+   static nl_catd s_Nlmsg_fd = (nl_catd) -1;
    static char * s_CatFileName = NULL;
 
    if ( s_First ) 
@@ -264,23 +260,9 @@ char * _DtHPrGetMessage(
          s_CatFileName = strdup(HELPPRINT_CAT);
       }
       s_First = 0;
-
-      lang = (char *) getenv ("LANG");
-
-      /* If LANG is not set or if LANG=C, then there
-       * is no need to open the message catalog - just
-       * return the built-in string "s".  */
-      if (!lang || !(strcmp (lang, "C"))) 
-         s_Nlmsg_fd = (nl_catd) -1;
-      else
-         s_Nlmsg_fd = catopen(s_CatFileName, 0);
+      s_Nlmsg_fd = CATOPEN(s_CatFileName, 0);
    }  /* end of first-time processing */
 
-   msg = catgets(s_Nlmsg_fd,set,n,s);
-   return (msg);
-
+   return CATGETS(s_Nlmsg_fd, set, n, s);
 }
 #endif  /* NO_MESSAGE_CATALOG */
-
-
-