[isdn4k-utils PATCH] Fix pppd crash in opt_proto handling

The function process_option() in options.c of pppd (2.4.7)
frees existing string pointers. So in our case
it frees a character array that's not allocated dynamically.

-> pppd sometimes crashes, sometimes not.
   Bug found with valgrind.

The default "HDLC" value is already set in "proto".

---
 pppdcapiplugin/capiplugin.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pppdcapiplugin/capiplugin.c b/pppdcapiplugin/capiplugin.c
index a663a0f..8ee644f 100644
--- a/pppdcapiplugin/capiplugin.c
+++ b/pppdcapiplugin/capiplugin.c
@@ -133,7 +133,7 @@ static STRINGLIST *clis;
 #define PROTO_ADSLPPPOA		7
 #define PROTO_ADSLPPPOALLC	8
 #define PROTO_ANALOGMODEM	9
-static char *opt_proto = "hdlc";
+static char *opt_proto = 0;
 static int proto = PROTO_HDLC;
 static int opt_avmadsl = 0;
 static int opt_vpi = -1; /* T-DSL: 1  */
@@ -501,7 +501,7 @@ static void plugin_check_options(void)
 	   if (!opt_channels) opt_channels = "1";
 	} else if (strcasecmp(opt_proto, "analogmodem") == 0) {
 	   proto = PROTO_ANALOGMODEM;
-	} else {
+	} else if (opt_proto != NULL) {
 	   option_error("capiplugin: unknown protocol \"%s\"", opt_proto);
 	   die(1);
 	}
-- 
1.9.3