need to include features.h to get uclibc defines

libc/sysdeps/linux/i386/crt1.S

@@ -54,6 +54,8 @@
 					NULL
 */
 
+#include <features.h>
+
 	.text
 	.globl	_start
 	.type	_start,@function

libc/sysdeps/linux/i386/syscall.S

@@ -19,6 +19,8 @@
  *         syscall(__NR_exit, 42);
  * and things will just work.
  */
+
+#include <features.h>
 	
 .text
 	.align 4