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/debug-generator/debug-generator.c

@@ -96,7 +96,7 @@ static int generate_mask_symlinks(void) {
                         return log_oom();
 
                 if (symlink("/dev/null", p) < 0) {
-                        log_error("Failed to create mask symlink %s: %m", p);
+                        log_error_errno(errno, "Failed to create mask symlink %s: %m", p);
                         r = -errno;
                 }
         }
@@ -125,7 +125,7 @@ static int generate_wants_symlinks(void) {
                 mkdir_parents_label(p, 0755);
 
                 if (symlink(f, p) < 0) {
-                        log_error("Failed to create wants symlink %s: %m", p);
+                        log_error_errno(errno, "Failed to create wants symlink %s: %m", p);
                         r = -errno;
                 }
         }