Remove sys/cdefs.h include, does not exist in musl libc

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

fparseln.c

@@ -24,11 +24,6 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: fparseln.c,v 1.10 2009/10/21 01:07:45 snj Exp $");
-#endif /* LIBC_SCCS and not lint */
-
 #include <assert.h>
 #include <errno.h>
 #include <stdio.h>