log: add an "error" parameter to all low-level logging calls and intrdouce log_error_errno() as log calls that take error numbers

This change has two benefits:

- The format string %m will now resolve to the specified error (or to
  errno if the specified error is 0. This allows getting rid of a ton of
  strerror() invocations, a function that is not thread-safe.

- The specified error can be passed to the journal in the ERRNO= field.

Now of course, we just need somebody to convert all cases of this:

        log_error("Something happened: %s", strerror(-r));

into thus:

        log_error_errno(-r, "Something happened: %m");

1 files changed, 1 insertions, 2 deletions

diff --git a/src/network/networkd-ipv4ll.c b/src/network/networkd-ipv4ll.c
index 5467bc372e..fd55f79693 100644
--- a/src/network/networkd-ipv4ll.c
+++ b/src/network/networkd-ipv4ll.c
@@ -40,8 +40,7 @@ static int ipv4ll_address_lost(Link *link) {
         if (r < 0)
                 return 0;
 
-        log_debug_link(link, "IPv4 link-local release %u.%u.%u.%u",
-                       ADDRESS_FMT_VAL(addr));
+        log_debug_link(link, "IPv4 link-local release %u.%u.%u.%u", ADDRESS_FMT_VAL(addr));
 
         r = address_new_dynamic(&address);
         if (r < 0) {