treewide: use log_*_errno whenever %m is in the format string

If the format string contains %m, clearly errno must have a meaningful
value, so we might as well use log_*_errno to have ERRNO= logged.

Using:
find . -name '*.[ch]' | xargs sed -r -i -e \
's/log_(debug|info|notice|warning|error|emergency)\((".*%m.*")/log_\1_errno(errno, \2/'

Plus some whitespace, linewrap, and indent adjustments.

src/core/execute.c

@@ -885,7 +885,7 @@ fail:
                 log_error("PAM failed: %s", pam_strerror(handle, pam_code));
                 err = -EPERM;  /* PAM errors do not map to errno */
         } else {
-                log_error("PAM failed: %m");
+                log_error_errno(errno, "PAM failed: %m");
                 err = -errno;
         }