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, 2 deletions

diff --git a/json.c b/json.c
index ed440e72..f5b59fba 100644
--- a/json.c
+++ b/json.c
@@ -67,10 +67,9 @@ PERMISSIONS
 #include <stdlib.h>
 #include <stdbool.h>
 #include <stdarg.h>
-#include <time.h>               /* for time_t */
 #include <ctype.h>
 
-#include "gpsd_config.h"	/* for strlcpy() prototype */
+#include "os_compat.h"
 #ifdef SOCKET_EXPORT_ENABLE
 #include "json.h"