libc: initial import from Harvey

Note that libc is what distinguish "native" software from "non-native"
in Jehanne: further C libraries can be ported to Jehanne, but this libc
will remain the main building block of the system.

Also note that a few files have not been ported from Harvey:

	- 9sys/pushtls.c
	- port/rijndael.c
	- port/rijndael.tbl
	- port/sha2.c

Pushtls.c depends on libmp and libsec so libc is not the appropriate place
for it. The other three will be moved to libsec.

sys/include/ctype.h

@@ -0,0 +1,38 @@
+/*
+ * This file is part of the UCB release of Plan 9. It is subject to the license
+ * terms in the LICENSE file found in the top-level directory of this
+ * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
+ * part of the UCB release of Plan 9, including this file, may be copied,
+ * modified, propagated, or distributed except according to the terms contained
+ * in the LICENSE file.
+ */
+
+#pragma	src	"/sys/src/libc/port"
+#pragma	lib	"libc.a"
+
+#define	_U	01
+#define	_L	02
+#define	_N	04
+#define	_S	010
+#define	_P	020
+#define	_C	040
+#define	_B	0100
+#define	_X	0200
+
+extern unsigned char	_ctype[];
+
+#define	isalpha(c)	(_ctype[(unsigned char)(c)]&(_U|_L))
+#define	isupper(c)	(_ctype[(unsigned char)(c)]&_U)
+#define	islower(c)	(_ctype[(unsigned char)(c)]&_L)
+#define	isdigit(c)	(_ctype[(unsigned char)(c)]&_N)
+#define	isxdigit(c)	(_ctype[(unsigned char)(c)]&_X)
+#define	isspace(c)	(_ctype[(unsigned char)(c)]&_S)
+#define	ispunct(c)	(_ctype[(unsigned char)(c)]&_P)
+#define	isalnum(c)	(_ctype[(unsigned char)(c)]&(_U|_L|_N))
+#define	isprint(c)	(_ctype[(unsigned char)(c)]&(_P|_U|_L|_N|_B))
+#define	isgraph(c)	(_ctype[(unsigned char)(c)]&(_P|_U|_L|_N))
+#define	iscntrl(c)	(_ctype[(unsigned char)(c)]&_C)
+#define	isascii(c)	((unsigned char)(c)<=0177)
+#define	_toupper(c)	((c)-'a'+'A')
+#define	_tolower(c)	((c)-'A'+'a')
+#define	toascii(c)	((c)&0177)