os/os2: add get_executable_path and get_executable_directory

core/os/os2/path_netbsd.odin

@@ -0,0 +1,24 @@
+package os2
+
+import "base:runtime"
+
+import "core:sys/posix"
+
+_get_executable_path :: proc(allocator: runtime.Allocator) -> (path: string, err: Error) {
+	TEMP_ALLOCATOR_GUARD()
+
+	buf := make([dynamic]byte, 1024, temp_allocator()) or_return
+	for {
+		n := posix.readlink("/proc/curproc/exe", raw_data(buf), len(buf))
+		if n < 0 {
+			err = _get_platform_error()
+			return
+		}
+
+		if n < len(buf) {
+			return clone_string(string(buf[:n]), allocator)
+		}
+
+		resize(&buf, len(buf)*2) or_return
+	}
+}