pppd/plugins: Add const qualifiers to eliminate warnings

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

Author: paulusmack

pppd/plugins/radius/radrealms.c

@@ -46,7 +46,7 @@ lookup_realm(char const *user,
 	     SERVER **authserver,
 	     SERVER **acctserver)
 {
-    char *realm;
+    const char *realm;
     FILE *fd;
     SERVER *accts, *auths, *s;
     char buffer[512], *p;

pppd/plugins/winbind.c

@@ -168,7 +168,7 @@ size_t strhex_to_str(unsigned char *p, size_t len, const char *strhex)
 	size_t num_chars = 0;
 	unsigned char   lonybble, hinybble;
 	const char     *hexchars = "0123456789ABCDEF";
-	char           *p1 = NULL, *p2 = NULL;
+	const char     *p1 = NULL, *p2 = NULL;
 
 	for (i = 0; i < len && strhex[i] != 0; i++) {
 		if (strncmp(hexchars, "0x", 2) == 0) {