--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/README.cross_compile	Thu Apr 21 14:57:45 2011 +0100
@@ -0,0 +1,69 @@
+
+Cross-Compiling DTN2
+====================
+
+(This file last updated June 14, 2006)
+
+The actual steps needed for cross compiling DTN2 will depend on the
+particular toolchain in use as well as the target architecture. This
+file defines steps for certain known-to-work configurations.
+
+Cross compilation toolchain installed on Linux
+----------------------------------------------
+
+In this configuration, we assume that some cross-compilation toolchain
+was installed with all toolchain executables prefixed by the name of
+the target system. In this example, assume that the target system is
+arm-linux, so all tools are named arm-linux-<tool>, and are installed
+into a directory on the system called /opt/arm-linux-toolchain/bin.
+
+First set the path to include the installed toolchain directory:
+
+% export PATH=/opt/arm-linux-toolchain/bin:$PATH
+
+Then download and unpack sources for tcl and berkeley db. The
+following will compile and install them into /opt/arm-linux-libraries.
+Note that BerkeleyDB is not required, so if you don't want it, you can
+skip that step and pass --without-db to the DTN2 configure invocation.
+
+(In the unpacked tcl source dir)
+% cd unix
+% CC=arm-linux-gcc ./configure --prefix=/opt/arm-linux-libraries
+% make
+% make install
+
+If the build presents trouble, the following note from the
+comp.lang.tcl archive may be helpful:
+
+   Re: multiple definition of `fixstrtod' while cross-compiling tcl
+   From: Eric Hassold <hassold at evolane.fr>
+   Date: Mon Dec 05 2005 - 22:33:38 CET
+
+   Tcl configure script makes some pessimistic assumptions when
+   cross-compiling (when AC_TRY_RUN can't run). One of them is guessing
+   libc has no strtod when small test program can't be run. Some AC_TRY_RUN
+   should actually be replaced by AC_TRY_LINK to provide better estimate.
+
+   Anyway, as a work-around, you may force configure detection, defining
+      export ac_cv_func_strtod=yes
+   before running ./configure. You may also have to force
+      export tcl_cv_strtod_buggy=1
+   so that Tcl will define its own fixstrtod() symbol, which will call
+   uclibc's strtod(). Works fine in our nightly built process, compiling
+   Tcl for arm-linux/uclibc.
+
+(In the unpacked Berkeley DB source dir)
+% cd build_unix
+% ../dist/configure --prefix=/opt/arm-linux-libraries \
+    --build=`uname -m` --host=arm-linux
+% make
+% make install
+
+The final step is to configure and build DTN2, again with the PATH set
+to include the cross-compilation toolchain and with tcl and Berkeley
+DB installed in /opt/arm-linux-libraries.
+
+% ./configure --build=`uname -m` --host=arm-linux \
+  --with-db=/opt/arm-linux-libraries  --with-tcl=/opt/arm-linux-libraries 
+% make
+