add initial CMake and Visual Studio build support

This moves the compatibility include files from include to
include/compat so we can use the awful MS C compiler
<../include/> trick to emulate the GNU #include_next extension.

This also removes a few old compat files we do not need anymore.

include/compat/sys/cdefs.h

@@ -0,0 +1,31 @@
+/*
+ * Public domain
+ * sys/cdefs.h compatibility shim
+ */
+
+#ifndef LIBCRYPTOCOMPAT_SYS_CDEFS_H
+#define LIBCRYPTOCOMPAT_SYS_CDEFS_H
+
+#ifdef _WIN32
+
+#define __warn_references(sym,msg)
+
+#else
+
+#include_next <sys/cdefs.h>
+
+#ifndef __warn_references
+
+#if defined(__GNUC__)  && defined (HAS_GNU_WARNING_LONG)
+#define __warn_references(sym,msg)          \
+  __asm__(".section .gnu.warning." __STRING(sym)  \
+         " ; .ascii \"" msg "\" ; .text");
+#else
+#define __warn_references(sym,msg)
+#endif
+
+#endif /* __warn_references */
+
+#endif /* _WIN32 */
+
+#endif /* LIBCRYPTOCOMPAT_SYS_CDEFS_H */

include/compat/sys/ioctl.h

@@ -0,0 +1,11 @@
+/*
+ * Public domain
+ * sys/ioctl.h compatibility shim
+ */
+
+#ifndef _WIN32
+#include_next <sys/ioctl.h>
+#else
+#include <win32netcompat.h>
+#define ioctl(fd, type, arg) ioctlsocket(fd, type, arg)
+#endif

include/compat/sys/mman.h

@@ -0,0 +1,19 @@
+/*
+ * Public domain
+ * sys/mman.h compatibility shim
+ */
+
+#include_next <sys/mman.h>
+
+#ifndef LIBCRYPTOCOMPAT_MMAN_H
+#define LIBCRYPTOCOMPAT_MMAN_H
+
+#ifndef MAP_ANON
+#ifdef MAP_ANONYMOUS
+#define MAP_ANON MAP_ANONYMOUS
+#else
+#error "System does not support mapping anonymous pages?"
+#endif
+#endif
+
+#endif

include/compat/sys/param.h

@@ -0,0 +1,15 @@
+/*
+ * Public domain
+ * sys/param.h compatibility shim
+ */
+
+#ifndef LIBCRYPTOCOMPAT_SYS_PARAM_H
+#define LIBCRYPTOCOMPAT_SYS_PARAM_H
+
+#ifdef _MSC_VER
+#include <winsock2.h>
+#else
+#include_next <sys/param.h>
+#endif
+
+#endif

include/compat/sys/select.h

@@ -0,0 +1,10 @@
+/*
+ * Public domain
+ * sys/select.h compatibility shim
+ */
+
+#ifndef _WIN32
+#include_next <sys/select.h>
+#else
+#include <win32netcompat.h>
+#endif

include/compat/sys/socket.h

@@ -0,0 +1,10 @@
+/*
+ * Public domain
+ * sys/socket.h compatibility shim
+ */
+
+#ifndef _WIN32
+#include_next <sys/socket.h>
+#else
+#include <win32netcompat.h>
+#endif

include/compat/sys/stat.h

@@ -0,0 +1,95 @@
+/*
+ * Public domain
+ * sys/stat.h compatibility shim
+ */
+
+#ifndef LIBCRYPTOCOMPAT_SYS_STAT_H
+#define LIBCRYPTOCOMPAT_SYS_STAT_H
+
+#ifdef _MSC_VER
+#include <windows.h>
+#include <../include/sys/stat.h>
+
+/* File type and permission flags for stat() */
+#if !defined(S_IFMT)
+#   define S_IFMT   _S_IFMT                     /* File type mask */
+#endif
+#if !defined(S_IFDIR)
+#   define S_IFDIR  _S_IFDIR                    /* Directory */
+#endif
+#if !defined(S_IFCHR)
+#   define S_IFCHR  _S_IFCHR                    /* Character device */
+#endif
+#if !defined(S_IFFIFO)
+#   define S_IFFIFO _S_IFFIFO                   /* Pipe */
+#endif
+#if !defined(S_IFREG)
+#   define S_IFREG  _S_IFREG                    /* Regular file */
+#endif
+#if !defined(S_IREAD)
+#   define S_IREAD  _S_IREAD                    /* Read permission */
+#endif
+#if !defined(S_IWRITE)
+#   define S_IWRITE _S_IWRITE                   /* Write permission */
+#endif
+#if !defined(S_IEXEC)
+#   define S_IEXEC  _S_IEXEC                    /* Execute permission */
+#endif
+#if !defined(S_IFIFO)
+#   define S_IFIFO _S_IFIFO                     /* Pipe */
+#endif
+#if !defined(S_IFBLK)
+#   define S_IFBLK   0                          /* Block device */
+#endif
+#if !defined(S_IFLNK)
+#   define S_IFLNK   0                          /* Link */
+#endif
+#if !defined(S_IFSOCK)
+#   define S_IFSOCK  0                          /* Socket */
+#endif
+
+#if defined(_MSC_VER)
+#   define S_IRUSR  S_IREAD                     /* Read user */
+#   define S_IWUSR  S_IWRITE                    /* Write user */
+#   define S_IXUSR  0                           /* Execute user */
+#   define S_IRGRP  0                           /* Read group */
+#   define S_IWGRP  0                           /* Write group */
+#   define S_IXGRP  0                           /* Execute group */
+#   define S_IROTH  0                           /* Read others */
+#   define S_IWOTH  0                           /* Write others */
+#   define S_IXOTH  0                           /* Execute others */
+#endif
+
+/* File type flags for d_type */
+#define DT_UNKNOWN  0
+#define DT_REG      S_IFREG
+#define DT_DIR      S_IFDIR
+#define DT_FIFO     S_IFIFO
+#define DT_SOCK     S_IFSOCK
+#define DT_CHR      S_IFCHR
+#define DT_BLK      S_IFBLK
+#define DT_LNK      S_IFLNK
+
+/* Macros for converting between st_mode and d_type */
+#define IFTODT(mode) ((mode) & S_IFMT)
+#define DTTOIF(type) (type)
+
+/*
+ * File type macros.  Note that block devices, sockets and links cannot be
+ * distinguished on Windows and the macros S_ISBLK, S_ISSOCK and S_ISLNK are
+ * only defined for compatibility.  These macros should always return false
+ * on Windows.
+ */
+#define	S_ISFIFO(mode) (((mode) & S_IFMT) == S_IFIFO)
+#define	S_ISDIR(mode)  (((mode) & S_IFMT) == S_IFDIR)
+#define	S_ISREG(mode)  (((mode) & S_IFMT) == S_IFREG)
+#define	S_ISLNK(mode)  (((mode) & S_IFMT) == S_IFLNK)
+#define	S_ISSOCK(mode) (((mode) & S_IFMT) == S_IFSOCK)
+#define	S_ISCHR(mode)  (((mode) & S_IFMT) == S_IFCHR)
+#define	S_ISBLK(mode)  (((mode) & S_IFMT) == S_IFBLK)
+
+#else
+#include_next <sys/stat.h>
+#endif
+
+#endif

include/compat/sys/time.h

@@ -0,0 +1,16 @@
+/*
+ * Public domain
+ * sys/time.h compatibility shim
+ */
+
+#ifndef LIBCRYPTOCOMPAT_SYS_TIME_H
+#define LIBCRYPTOCOMPAT_SYS_TIME_H
+
+#ifdef _MSC_VER
+#include <winsock2.h>
+int gettimeofday(struct timeval *tp, void *tzp);
+#else
+#include_next <sys/time.h>
+#endif
+
+#endif

include/compat/sys/types.h

@@ -0,0 +1,43 @@
+/*
+ * Public domain
+ * sys/types.h compatibility shim
+ */
+
+#ifndef LIBCRYPTOCOMPAT_SYS_TYPES_H
+#define LIBCRYPTOCOMPAT_SYS_TYPES_H
+
+#ifdef _MSC_VER
+#include <../include/sys/types.h>
+#else
+#include_next <sys/types.h>
+#endif
+
+#include <stdint.h>
+
+#ifdef __MINGW32__
+#include <_bsd_types.h>
+#endif
+
+#ifdef _MSC_VER
+typedef unsigned char   u_char;
+typedef unsigned short  u_short;
+typedef unsigned int    u_int;
+
+#include <basetsd.h>
+typedef SSIZE_T ssize_t;
+
+#ifndef SSIZE_MAX
+#ifdef _WIN64
+#define SSIZE_MAX _I64_MAX
+#else
+#define SSIZE_MAX INT_MAX
+#endif
+#endif
+
+#endif
+
+#if !defined(HAVE_ATTRIBUTE__BOUNDED__) && !defined(__bounded__)
+# define __bounded__(x, y, z)
+#endif
+
+#endif

include/compat/sys/uio.h

@@ -0,0 +1,17 @@
+/*
+ * Public domain
+ * sys/select.h compatibility shim
+ */
+
+#ifndef _WIN32
+#include_next <sys/uio.h>
+#else
+
+#include <sys/types.h>
+
+struct iovec {
+	void *iov_base;
+	size_t iov_len;
+};
+
+#endif