Cross-compilation fixes

Switch from host OS detection to target OS detection.
Complain about unknown target OS/architecture.
Disable annoying format string warnings on DJGPP.

Native and cross-compilation now usually just require setting CC.
make CC=i586-pc-msdosdjgpp-gcc
make CC="clang -m64"
make CC=i686-w64-mingw32-gcc

Tested for a boatload of native and cross compilation configurations.

There is a new target "make libpayload" in case you don't want to
specify all tools by hand.

Corresponding to flashrom svn r1476.

Signed-off-by: Carl-Daniel Hailfinger <>
Acked-by: David Hendricks <>
diff --git a/os.h b/os.h
new file mode 100644
index 0000000..4ca7bb5
--- /dev/null
+++ b/os.h
@@ -0,0 +1,58 @@
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2011 Carl-Daniel Hailfinger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+ * Header file for OS checking.
+ */
+// Solaris
+#if defined (__sun) && (defined(__i386) || defined(__amd64))
+#define __FLASHROM_OS__ "SunOS"
+// OS X
+#elif defined(__MACH__) && defined(__APPLE__)
+#define __FLASHROM_OS__ "Darwin"
+// FreeBSD
+#elif defined(__FreeBSD__)
+#define __FLASHROM_OS__ "FreeBSD"
+// DragonFlyBSD
+#elif defined(__DragonFly__)
+#define __FLASHROM_OS__ "DragonFlyBSD"
+// NetBSD
+#elif defined(__NetBSD__)
+#define __FLASHROM_OS__ "NetBSD"
+// OpenBSD
+#elif defined(__OpenBSD__)
+#define __FLASHROM_OS__ "OpenBSD"
+#elif defined(__DJGPP__)
+#define __FLASHROM_OS__ "DOS"
+// MinGW (always has _WIN32 available)
+#elif defined(__MINGW32__)
+#define __FLASHROM_OS__ "MinGW"
+// Cygwin (usually without _WIN32)
+#elif defined( __CYGWIN__)
+#define __FLASHROM_OS__ "Cygwin"
+// libpayload
+#elif defined(__LIBPAYLOAD__)
+#define __FLASHROM_OS__ "libpayload"
+// Linux
+#elif defined(__linux__)
+#define __FLASHROM_OS__ "Linux"