first version of datetime lib

libs/datetime/time_functions.c

@@ -0,0 +1,12 @@
+#include "time_functions.h"
+
+GroundValue datetime_NowEpoch(GroundScope* scope, List args) {
+    // grab time from system clock
+    struct timespec ts;
+    clock_gettime(CLOCK_REALTIME, &ts);
+
+    // convert it to secs and return it
+    double secsSinceEpoch = (double)ts.tv_sec + (double)ts.tv_nsec / 1e9;
+
+    return groundCreateValue(DOUBLE, secsSinceEpoch);
+}