Content:
 1. Introduction
 2. Necessary arguments for "configure"
 3. Necessary environment variables for "configure"
 4. Example


1. INTRODUCTION
===============

This document discusses cross-compiling VIM on Unix-like systems. We assume
you are already familiar with cross-compiling and have a working cross-compile
environment with at least the following components:

 * a cross-compiler
 * a libc to link against
 * ncurses library to link against

Discussing how to set up a cross-compile environment would go beyond the scope
of this document. See http://www.kegel.com/crosstool/ for more information and
a script that aids in setting up such an environment.


The problem is that "configure" needs to compile and run small test programs
to check for certain features. Running these test programs can't be done when
cross-compiling so we need to pass the results these checks would produce via
environment variables. See the list of variables and the examples at the end of
this document.


2. NECESSARY ARGUMENTS FOR "configure"
======================================

You need to set the following "configure" command line switches:

--build=... :
	The build system (i.e. the platform name of the system you compile on
	right now).
	For example, "i586-linux".

--host=... :
	The system on which VIM will be run. Quite often this the name of your
	cross-compiler without the "-gcc".
	For example, "powerpc-603-linux-gnu".

--target=... :
	Only relevant for compiling compilers. Set this to the same value as
	--host.

--with-tlib=... :
	Which terminal library to.
	For example, "ncurses".


3. NECESSARY ENVIRONMENT VARIABLES FOR "configure"
==================================================

Additionally to the variables listed here you might want to set the CPPFLAGS
environment variable to enable optimization for your target system (e.g.
"CPPFLAGS=-march=arm5te").

The following variables need to be set:

ac_cv_sizeof_int:
	The size of an "int" C type in bytes. Should be "4" on all 32bit
	machines.

vi_cv_path_python_conf:
	If Python support is enabled, set this variables to the path for
	Python's library implementation. This is a path like
	"/usr/lib/pythonX.Y/config" (the directory contains a file
	"config.c").

vi_cv_var_python_epfx:
	If Python support is enabled, set this variables to the execution
	prefix of your Python interpreter (that is, where it thinks it is
	running).
	This is the output of the following Python script:
		import sys; print sys.exec_prefix

vi_cv_var_python_pfx:
	If Python support is enabled, set this variables to the prefix of your
	Python interpreter (that is, where was installed).
	This is the output of the following Python script:
		import sys; print sys.prefix

vi_cv_var_python_version:
	If Python support is enabled, set this variables to the version of the
	Python interpreter that will be used.
	This is the output of the following Python script:
		import sys; print sys.version[:3]

vim_cv_bcopy_handles_overlap:
	Whether the "memmove" C library call is able to copy overlapping
	memory regions. Set to "yes" if it does or "no" if it does not.
	You only need to set this if vim_cv_memmove_handles_overlap is set
	to "no".

vim_cv_getcwd_broken:
	Whether the "getcwd" C library call is broken. Set to "yes" if you
	know that "getcwd" is implemented as 'system("sh -c pwd")', set to
	"no" otherwise.

vim_cv_memcpy_handles_overlap:
	Whether the "memcpy" C library call is able to copy overlapping
	memory regions. Set to "yes" if it does or "no" if it does not.
	You only need to set this if both vim_cv_memmove_handles_overlap
	and vim_cv_bcopy_handles_overlap are set to "no".

vim_cv_memmove_handles_overlap:
	Whether the "memmove" C library call is able to copy overlapping
	memory regions. Set to "yes" if it does or "no" if it does not.

vim_cv_stat_ignores_slash:
	Whether the "stat" C library call ignores trailing slashes in the path
	name. Set to "yes" if it ignores them or "no" if it does not ignore
	them.

vim_cv_tgetent:
	Whether the "tgetent" terminal library call returns a zero or non-zero
	value when it encounters an unknown terminal. Set to either the string
	"zero" or "non-zero", corresponding.

vim_cv_terminfo:
	Whether the environment has terminfo support. Set to "yes" if so,
	otherwise set to "no".

vim_cv_toupper_broken:
	Whether the "toupper" C library function works correctly. Set to "yes"
	if you know it's broken, otherwise set to "no".

vim_cv_tty_group:
	The default group of pseudo terminals. Either set to the numeric value
	of the your tty group or to "world" if they are world accessable.

vim_cv_tty_mode:
	The default mode of pseudo terminals if they are not world accessable.
	Most propably the value "0620".


4. EXAMPLE:
===========

Assuming the target system string is "armeb-xscale-linux-gnu" (a Intel XScale
system) with glibc and ncurses, the call to configure would look like this:

ac_cv_sizeof_int=4 \
vim_cv_getcwd_broken=no \
vim_cv_memmove_handles_overlap=yes \
vim_cv_stat_ignores_slash=yes \
vim_cv_tgetent=zero \
vim_cv_terminfo=yes \
vim_cv_toupper_broken=no \
vim_cv_tty_group=world \
./configure \
	--build=i586-linux \
	--host=armeb-xscale-linux-gnu \
	--target=armeb-xscale-linux-gnu \
	--with-tlib=ncurses



Written 2007 by Marc Haisenko <marc@darkdust.net> for the VIM project.