implement bsd's, same as darwin

core/prof/spall/spall_unix.odin

@@ -0,0 +1,57 @@
+//+private
+//+build darwin, freebsd, openbsd
+package spall
+
+// Only for types.
+import "core:os"
+
+when ODIN_OS == .Darwin {
+	foreign import libc "system:System.framework"
+} else {
+	foreign import libc "system:c"
+}
+
+timespec :: struct {
+	tv_sec:  i64, // seconds
+	tv_nsec: i64, // nanoseconds
+}
+
+foreign libc {
+	__error :: proc() -> ^i32 ---
+	@(link_name="write")         _unix_write         :: proc(handle: os.Handle, buffer: rawptr, count: uint) -> int ---
+	@(link_name="clock_gettime") _unix_clock_gettime :: proc(clock_id: u64, timespec: ^timespec) -> i32 ---
+}
+
+@(no_instrumentation)
+get_last_error :: proc "contextless" () -> int {
+	return int(__error()^)
+}
+
+MAX_RW :: 0x7fffffff
+
+@(no_instrumentation)
+_write :: proc "contextless" (fd: os.Handle, data: []byte) -> (n: int, err: os.Errno) #no_bounds_check /* bounds check would segfault instrumentation */ {
+	if len(data) == 0 {
+		return 0, os.ERROR_NONE
+	}
+
+	for n < len(data) {
+		chunk := data[:min(len(data), MAX_RW)]
+		written := _unix_write(fd, raw_data(chunk), len(chunk))
+		if written < 0 {
+			return n, os.Errno(get_last_error())
+		}
+		n += written
+	}
+
+	return n, os.ERROR_NONE
+}
+
+CLOCK_MONOTONIC_RAW :: 4 // NOTE(tetra): "RAW" means: Not adjusted by NTP.
+
+@(no_instrumentation)
+_tick_now :: proc "contextless" () -> (ns: i64) {
+	t: timespec
+	_unix_clock_gettime(CLOCK_MONOTONIC_RAW, &t)
+	return t.tv_sec*1e9 + t.tv_nsec
+}