From 9bf2a7c888312f197bbad77f47c067f856900578 Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Fri, 20 Sep 2019 22:09:49 +0000 Subject: INSTALL now explains the easy cross-compilation --- INSTALL | 46 +++++++++++++++++++++------------------------- 1 file changed, 21 insertions(+), 25 deletions(-) (limited to 'INSTALL') diff --git a/INSTALL b/INSTALL index 57bfa54..e98ff41 100644 --- a/INSTALL +++ b/INSTALL @@ -102,31 +102,27 @@ the name of the sysdeps directory at build time, and can depend on its contents - that's how skarnet.org packages are easily made portable. However, when the host differs from the target - the cross-compilation -case - those build-time tests are invalid. So you must provide -configure with a precomputed sysdeps directory, containing valid -sysdeps values for your target. - - Use the --with-sysdeps=DIR option to specify DIR as a sysdeps -directory for your target. Also use the --host=HOST option, HOST being -the triplet for your target. - - If you know the peculiarities of your target system, you can build -a sysdeps directory by hand. However, a much easier, and recommended, -method of obtaining sysdeps, is to natively determine them (via -./configure) in a virtual machine, for instance provided by qemu. If you -are using Linux, simple root filesystems bootable with qemu for testing -purposes are available at Aboriginal Linux: http://landley.net/aboriginal/ - Precomputed sysdeps for various targets may also be available on -skarnet.org or on third-party sites. - - Once you have gathered your sysdeps, for any skarnet.org package: - * make sure the binaries of your cross-toolchain (HOST-gcc, HOST-ld, -HOST-ar, etc.) are accessible via your PATH environment variable - * give the correct --with-sysdeps option to ./configure - * give the correct --host option - * for --prefix, --bindir and other paths, always use the run-time path - * to install the cross-compiled package in a staging directory /your/stage, - perform "make install DESTDIR=/your/stage" +case - some of those build-time tests, i.e. the ones that require +code execution on the target, are invalid. So you must manually +provide configure with appropriate values for the list of sysdeps that +cannot be autodetected. + For a sysdep named K with a value V, the correct option to give to +configure is: --with-sysdep-K=V + Most of the time, sysdeps have a boolean value, so the correct V is +"yes" or "no". + For instance, to say that the target has a working pseudorandom +number generator in /dev/urandom, you would give the following +option to configure: --with-sysdep-devurandom=yes + + ./configure --help lists all the sysdeps you need to manually +provide a value for when cross-compiling. + + Note that you can provide manual sysdeps values at any time, +for any existing sysdep, to bypass autodetection - and you can +even do it when building natively. It's just not recommended +(you should let skalibs autodetect everything it can), and +and it's only mandatory for a small subset of sysdeps in the +cross-compilation case. * The slashpackage convention -- cgit v1.2.3