Merge remote-tracking branch 'origin/feat/rsync-stderr-mode' into dev

# Conflicts:
#	RSYNC_COMPAT.md
#	src/shared/log.c
#	src/shared/log.h
#	tests/test_client_cli.c

src/client/usage.c

@@ -62,6 +62,7 @@ void print_usage(void) {
   printf("  -h, --human-readable  Print byte sizes in human-readable form\n");
   printf("  --max-depth <n>     Maximum directory depth (0=unlimited)\n");
   printf("  --log-file <path>   Write log messages to file\n");
+  printf("  --stderr=MODE       Route logging to stderr: errors or all\n");
   printf("  --partial           Keep partial files on interrupted transfer\n");
   printf("  --partial-dir <dir> Directory for partial files\n");
   printf("  --fastsync-server-path <path>\n");