Add --clk-tck to set the clock unit

* main.c (argp_parser, main): Add and parse the --clk-tck option.
* main.h: Publish opt_clk_tck.
* process.c (sc_tc): Use the user-provided clock frequency.
* rootdir.c (rootdir_gc_stat): Likewise.

1 files changed, 2 insertions, 0 deletions

diff --git a/main.h b/main.h
new file mode 100644
index 00000000..4b2ef9a1
--- /dev/null
+++ b/main.h
@@ -0,0 +1,2 @@
+/* Startup options */
+extern int opt_clk_tck;