box2d: update to 3.1.0

vendor/libc/sched.odin

@@ -0,0 +1,30 @@
+package odin_libc
+
+import "core:time"
+
+Clock :: enum i32 {
+	Monotonic = 1,
+}
+
+Time_Spec :: struct {
+	tv_sec:  i64,
+	tv_nsec: i64,
+}
+
+@(require, linkage="strong", link_name="clock_gettime")
+clock_gettine :: proc "c" (clockid: Clock, tp: ^Time_Spec) -> i32 {
+	switch clockid {
+	case .Monotonic:
+		tick := time.tick_now()
+		tp.tv_sec = tick._nsec/1e9
+		tp.tv_nsec = tick._nsec%1e9/1000
+		return 0
+
+	case: return -1
+	}
+}
+
+@(require, linkage="strong", link_name="sched_yield")
+sched_yield :: proc "c" () -> i32 {
+	return 0
+}