Initial creation of os_compat.h.

This creates a header for os_compat.c, and moves the related
prototypes into it from gpsd_config.h (as created by SConstruct),
after adding references to it to gpsd.h (via gpsd.h-tail) and a few
other sources that need it but don't include gpsd.h.

It also removes includes of <time.h> in the places where they were
only needed for the code now removed from gpsd_config.h.

TESTED:
Ran "scons build-all check" on OSX 10.9 (with strlcat/strlcpy but no
clock_gettime), OSX 10.12 (with strlcat/strlcpy and clock_gettime),
and Ubuntu 14 (with clock_gettime but no strlcat/strlcpy).  Also
verified that fallback versions were not being included where
unnecessary.

1 files changed, 1 insertions, 0 deletions

diff --git a/cgps.c b/cgps.c
index e5b749a3..56f90736 100644
--- a/cgps.c
+++ b/cgps.c
@@ -101,6 +101,7 @@
 #include "compiler.h"	/* for UNUSED */
 #include "gpsdclient.h"
 #include "revision.h"
+#include "os_compat.h"
 
 static struct gps_data_t gpsdata;
 static time_t status_timer;	/* Time of last state change. */