add get core count

core/os/os_freebsd.odin

@@ -287,6 +287,7 @@ foreign libc {
 	
 	@(link_name="getenv")           _unix_getenv        :: proc(cstring) -> cstring ---
 	@(link_name="realpath")         _unix_realpath      :: proc(path: cstring, resolved_path: rawptr) -> rawptr ---
+	@(link_name="sysctlbyname")     _sysctlbyname       :: proc(path: cstring, oldp: rawptr, oldlenp: rawptr, newp: rawptr, newlen: int) -> c.int ---
 
 	@(link_name="exit")             _unix_exit          :: proc(status: c.int) -> ! ---
 }
@@ -702,6 +703,18 @@ get_page_size :: proc() -> int {
 	return page_size
 }
 
+get_processor_thread_count :: proc() -> int {
+	count : int = 0
+	count_size := size_of(count)
+	if _sysctlbyname("hw.logicalcpu", rawptr(count), rawptr(count_size), 0, 0) == 0 {
+		if count > 0 {
+			return count
+		}
+	}
+
+	return 1
+}
+
 
 _alloc_command_line_arguments :: proc() -> []string {
 	res := make([]string, len(runtime.args__))