Add support for building native win32 tools

Add support for compiling the host tools in the tools directory using
the MinGW toolchain.  This produces executables which can be used on
standard Windows computers without requiring cygwin.

One must specify the MinGW compiler and strip utilities as if they
were the host toolchain in order to build win32 executables, eg:

make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>

tools/mingw_support.c

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2008 Extreme Engineering Solutions, Inc.
+ *
+ * mmap/munmap implementation derived from:
+ * Clamav Native Windows Port : mmap win32 compatibility layer
+ * Copyright (c) 2005-2006 Gianluigi Tiesi <sherpya@netfarm.it>
+ * Parts by Kees Zeelenberg <kzlg@users.sourceforge.net> (LibGW32C)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this software; if not, write to the
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "mingw_support.h"
+#include <stdio.h>
+#include <stdint.h>
+#include <errno.h>
+#include <io.h>
+
+int fsync(int fd)
+{
+	return _commit(fd);
+}
+
+void *mmap(void *addr, size_t len, int prot, int flags, int fd, int offset)
+{
+	void *map = NULL;
+	HANDLE handle = INVALID_HANDLE_VALUE;
+	DWORD cfm_flags = 0, mvf_flags = 0;
+
+	switch (prot) {
+	case PROT_READ | PROT_WRITE:
+		cfm_flags = PAGE_READWRITE;
+		mvf_flags = FILE_MAP_ALL_ACCESS;
+		break;
+	case PROT_WRITE:
+		cfm_flags = PAGE_READWRITE;
+		mvf_flags = FILE_MAP_WRITE;
+		break;
+	case PROT_READ:
+		cfm_flags = PAGE_READONLY;
+		mvf_flags = FILE_MAP_READ;
+		break;
+	default:
+		return MAP_FAILED;
+	}
+
+	handle = CreateFileMappingA((HANDLE) _get_osfhandle(fd), NULL,
+				cfm_flags, HIDWORD(len), LODWORD(len), NULL);
+	if (!handle)
+		return MAP_FAILED;
+
+	map = MapViewOfFile(handle, mvf_flags, HIDWORD(offset),
+			LODWORD(offset), len);
+	CloseHandle(handle);
+
+	if (!map)
+		return MAP_FAILED;
+
+	return map;
+}
+
+int munmap(void *addr, size_t len)
+{
+	if (!UnmapViewOfFile(addr))
+		return -1;
+
+	return 0;
+}