Revert "odhcp6c: Replace strerror(errno) with %m"

The code is ISO C source enforced by the usage of the pedantic compile
option; using %m triggers the compiler warning "error: ISO C does not
support the '%m' gnu_printf format [-Werror=format=]" which breaks
compilation due to Werror being set set.

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

CMakeLists.txt

@@ -5,7 +5,7 @@ cmake_policy(SET CMP0015 NEW)
 project(odhcp6c C)
 set(CMAKE_SHARED_LIBRARY_LINK_C_FLAGS "")
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g -std=c99")
-add_definitions(-D_GNU_SOURCE -Wall -Werror -Wextra)
+add_definitions(-D_GNU_SOURCE -Wall -Werror -Wextra -pedantic)
 
 if(${EXT_PREFIX_CLASS})
 	add_definitions(-DEXT_PREFIX_CLASS=${EXT_PREFIX_CLASS})

src/dhcpv6.c

@@ -522,9 +522,9 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 	if (sendmsg(sock, &msg, 0) < 0) {
 		char in6_str[INET6_ADDRSTRLEN];
 
-		syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%m)",
+		syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
 			inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
-				in6_str, sizeof(in6_str)));
+				in6_str, sizeof(in6_str)), strerror(errno));
 	}
 }
 

src/odhcp6c.c

@@ -255,14 +255,15 @@ int main(_unused int argc, char* const argv[])
 			init_dhcpv6(ifname, client_options, sol_timeout) ||
 			ra_init(ifname, &ifid, ra_options, ra_holdoff_interval) ||
 			script_init(script, ifname)) {
-		syslog(LOG_ERR, "failed to initialize: %m");
+		syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 		return 3;
 	}
 
 	if (daemonize) {
 		openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 		if (daemon(0, 0)) {
-			syslog(LOG_ERR, "Failed to daemonize: %m");
+			syslog(LOG_ERR, "Failed to daemonize: %s",
+					strerror(errno));
 			return 4;
 		}