Provide our own newlib libc

Newlib 2.2.0 w/ nan ofeatures, xtensa patches, locking
implementation.

Built from https://github.com/projectgus/newlib-xtensa
branch xtensa-2_2_0-lock
commit daa6ae40cdc8099f54c3e68a586fc1b906169c5a

For more details, see:
https://github.com/SuperHouse/esp-open-rtos/wiki/libc-configuration

Closes #1

libc/xtensa-lx106-elf/include/sys/param.h

@@ -0,0 +1,28 @@
+/* This is a dummy <sys/param.h> file, not customized for any
+   particular system.  If there is a param.h in libc/sys/SYSDIR/sys,
+   it will override this one.  */
+
+#ifndef _SYS_PARAM_H
+# define _SYS_PARAM_H
+
+#include <sys/config.h>
+#include <sys/syslimits.h>
+#include <machine/endian.h>
+#include <machine/param.h>
+
+#ifndef HZ
+# define HZ (60)
+#endif
+#ifndef NOFILE
+# define NOFILE	(60)
+#endif
+#ifndef PATHSIZE
+# define PATHSIZE (1024)
+#endif
+
+#define MAXPATHLEN PATH_MAX
+
+#define MAX(a,b) ((a) > (b) ? (a) : (b))
+#define MIN(a,b) ((a) < (b) ? (a) : (b))
+
+#endif