Port some of the base module to FreeBSD. Extracted from...

base/time_posix.cc

Index: base/time_posix.cc
===================================================================
--- base/time_posix.cc	(revision 24904)
+++ base/time_posix.cc	(working copy)
@@ -143,10 +143,11 @@
 }
 
 // TimeTicks ------------------------------------------------------------------
+// FreeBSD 6 has CLOCK_MONOLITHIC but defines _POSIX_MONOTONIC_CLOCK to -1.
+#if (defined(OS_POSIX) &&                                               \
+     defined(_POSIX_MONOTONIC_CLOCK) && _POSIX_MONOTONIC_CLOCK >= 0) || \
+    defined(OS_FREEBSD)
 
-#if defined(OS_POSIX) && \
-    defined(_POSIX_MONOTONIC_CLOCK) && _POSIX_MONOTONIC_CLOCK >= 0
-
 // static
 TimeTicks TimeTicks::Now() {
   uint64_t absolute_micro;