fnmatch.c: Update to version in OpenBSD HEAD

Upgrade fnmatch.c from OpenBSD version 1.13 to 1.16.
This is needed primarily to address CVE-2011-0419.

This is a straight copy from upstream's version at
http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libc/gen/fnmatch.c and
incorporates the following changes:

Revision 1.16:
New fnmatch(3) implementation which is not recursive.
Written and provided under BSD licence by William A. Rowe Jr.
Originally released in Apache APR-1.4.5.
Merged class matching code from r1.14 and PATH_MAX check from r1.15.
ok miod millert

Revision 1.15:
Put a limit on recursion during matching, and reject input of size greater
or equal PATH_MAX. Based on similar fix made in NetBSD.
ok miod@ millert@

Revision 1.14:
POSIX character class support for fnmatch(3) and glob(3).  OK deraadt@

Version 1.14 introduced charclasses.h, which we copy unmodified
from upstream version 1.1.
http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libc/gen/charclass.h

Bug: 3435120
Change-Id: I45133468f0c3d439fd10eb087a1c647799f9d25b
diff --git a/libc/unistd/charclass.h b/libc/unistd/charclass.h
new file mode 100644
index 0000000..5edb2c1
--- /dev/null
+++ b/libc/unistd/charclass.h
@@ -0,0 +1,29 @@
+/*
+ * Public domain, 2008, Todd C. Miller <Todd.Miller@courtesan.com>
+ *
+ * $OpenBSD: charclass.h,v 1.1 2008/10/01 23:04:13 millert Exp $
+ */
+
+/*
+ * POSIX character class support for fnmatch() and glob().
+ */
+static struct cclass {
+	const char *name;
+	int (*isctype)(int);
+} cclasses[] = {
+	{ "alnum",	isalnum },
+	{ "alpha",	isalpha },
+	{ "blank",	isblank },
+	{ "cntrl",	iscntrl },
+	{ "digit",	isdigit },
+	{ "graph",	isgraph },
+	{ "lower",	islower },
+	{ "print",	isprint },
+	{ "punct",	ispunct },
+	{ "space",	isspace },
+	{ "upper",	isupper },
+	{ "xdigit",	isxdigit },
+	{ NULL,		NULL }
+};
+
+#define NCCLASSES	(sizeof(cclasses) / sizeof(cclasses[0]) - 1)