Merge pull request #1020 from AtomicGameEngine/JME-ATOMIC-FIXCIVETWEB

Another attempt at civetweb Xcode 8 fix

Source/ThirdParty/Civetweb/src/civetweb.c

@@ -132,26 +132,11 @@ mg_static_assert(sizeof(void *) >= sizeof(int), "data type size check");
 #include <mach/mach_time.h>
 #include <assert.h>
 
-// ATOMIC BEGIN
-/* Determine if the current OSX version supports clock_gettime */
-#ifdef __APPLE__
-#include <AvailabilityMacros.h>
-#ifndef MAC_OS_X_VERSION_10_12
-#define MAC_OS_X_VERSION_10_12 101200
-#endif
-#endif
-
-// TODO: Once we get to the point 10.12 is required, make sure civetweb itself has been updated!
-// Instead of using MAC_OS_X_VERSION_MIN_REQUIRED, which it doesn't appear time.h is guarded by, use MAC_OS_X_VERSION_MAX_ALLOWED
-#define CIVETWEB_APPLE_HAVE_CLOCK_GETTIME defined(__APPLE__) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_12
-#if !(CIVETWEB_APPLE_HAVE_CLOCK_GETTIME)
-// ATOMIC END
-
 /* clock_gettime is not implemented on OSX prior to 10.12 */
-int clock_gettime(int clk_id, struct timespec *t);
+int _civet_clock_gettime(int clk_id, struct timespec *t);
 
 int
-clock_gettime(int clk_id, struct timespec *t)
+_civet_clock_gettime(int clk_id, struct timespec *t)
 {
     memset(t, 0, sizeof(*t));
     if (clk_id == CLOCK_REALTIME) {
@@ -191,6 +176,23 @@ clock_gettime(int clk_id, struct timespec *t)
     }
     return -1; /* EINVAL - Clock ID is unknown */
 }
+
+/* if clock_gettime is declared, then __CLOCK_AVAILABILITY will be defined */
+#ifdef __CLOCK_AVAILABILITY
+/* If we compiled with Mac OSX 10.12 or later, then clock_gettime will be declared
+ * but it may be NULL at runtime. So we need to check before using it. */
+int _civet_safe_clock_gettime(int clk_id, struct timespec *t);
+
+int
+_civet_safe_clock_gettime(int clk_id, struct timespec *t) {
+    if( clock_gettime ) {
+        return clock_gettime(clk_id, t);
+    }
+    return _civet_clock_gettime(clk_id, t);
+}
+#define clock_gettime _civet_safe_clock_gettime
+#else
+#define clock_gettime _civet_clock_gettime
 #endif
 #endif