tlsdated: add jitter (-j).

We check for steady-state updates randomly at any time between
(base-jitter,base+jitter). The jitter is generated using libc rand(), seeded
with either some bytes from /dev/urandom (if available) or the time (if not). We
don't particularly need strong randomness here.

Signed-off-by: Elly Fong-Jones <[email protected]>
(cherry picked from commit a8545b2af134f53247bd76507676bc0e3f1e6112)
diff --git a/CHANGELOG b/CHANGELOG
index fb7603c..754a0f6 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -9,6 +9,7 @@
   Add support for lcov/gcov at build time
     see ./configure --enable-code-coverage-checks and make lcov
   Don't hardfail if DEFAULT_RTC_DEVICE cannot be opened, even if desired
+  Support -j to add jitter to tlsdated time checks.
 0.0.4 Wed 7 Nov, 2012
   Fixup CHANGELOG and properly tag
     Version Numbers Are Free! Hooray!