ppp: Replace K&R style C declarations

GCC uses C23 standard by default which does not allow
K&R style declarations

(From OE-Core rev: acc41d7f912bf9d3ee142a02d0b64cf9ff6f226e)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-connectivity/ppp/ppp/0001-pppdump-Fixed-building-with-GCC-15-548.patch

@@ -0,0 +1,75 @@
+From 44a766a3d086f10cb584a0c423e5bed6af2e3615 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Jaroslav=20=C5=A0karvada?= <jskarvad@redhat.com>
+Date: Thu, 27 Feb 2025 23:00:16 +0100
+Subject: [PATCH] pppdump: Fixed building with GCC 15 (#548)
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+GCC 15 defaults to C23 which does not allow K&R declarations.
+
+Credit Yaakov Selkowitz in:
+https://src.fedoraproject.org/rpms/ppp/pull-request/12
+
+Upstream-Status: Backport [https://github.com/ppp-project/ppp/pull/548]
+
+Signed-off-by: Jaroslav Škarvada <jskarvad@redhat.com>
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+---
+ pppdump/pppdump.c | 20 +++++++-------------
+ 1 file changed, 7 insertions(+), 13 deletions(-)
+
+diff --git a/pppdump/pppdump.c b/pppdump/pppdump.c
+index c24208a..1534036 100644
+--- a/pppdump/pppdump.c
++++ b/pppdump/pppdump.c
+@@ -42,14 +42,12 @@ int tot_sent, tot_rcvd;
+ extern int optind;
+ extern char *optarg;
+ 
+-void dumplog();
+-void dumpppp();
+-void show_time();
++void dumplog(FILE *);
++void dumpppp(FILE *);
++void show_time(FILE *, int);
+ 
+ int
+-main(ac, av)
+-    int ac;
+-    char **av;
++main(int ac, char **av)
+ {
+     int i;
+     char *p;
+@@ -97,8 +95,7 @@ main(ac, av)
+ }
+ 
+ void
+-dumplog(f)
+-    FILE *f;
++dumplog(FILE *f)
+ {
+     int c, n, k, col;
+     int nb, c2;
+@@ -241,8 +238,7 @@ struct pkt {
+ unsigned char dbuf[8192];
+ 
+ void
+-dumpppp(f)
+-    FILE *f;
++dumpppp(FILE *f)
+ {
+     int c, n, k;
+     int nb, nl, dn, proto, rv;
+@@ -375,9 +371,7 @@ dumpppp(f)
+ }
+ 
+ void
+-show_time(f, c)
+-    FILE *f;
+-    int c;
++show_time(FILE *f, int c)
+ {
+     time_t t;
+     int n;

meta/recipes-connectivity/ppp/ppp_2.5.2.bb

@@ -23,6 +23,7 @@ SRC_URI = "https://download.samba.org/pub/${BPN}/${BP}.tar.gz \
            file://ppp_on_boot \
            file://provider \
            file://ppp@.service \
+           file://0001-pppdump-Fixed-building-with-GCC-15-548.patch \
            "
 
 SRC_URI[sha256sum] = "47da358de54a10cb10bf6ff2cf9b1c03c0d3555518f6182e8f701b8e55733cb2"