On Thu, Jun 28, 2012 at 12:29:25PM +0100, Simon McVittie wrote: > On 28/06/12 10:43, Svante Signell wrote: > > The situation is even more complicated if compiling for different OSes: > > Like as host (build) Linux:i386 and guest (target) kFreeBSD:amd64 or > > Hurd:i386. Any plans to support such combinations with > > cross-build-essential? > > It shouldn't differ from compiling for different CPUs: the key problem > in cross-compilation is "your build system can't run your host system's > binaries", which you can arrive at either via differing OSs or differing > CPUs. (Or both, of course.) It's not just that: if qemu-user is enabled, you will be able to run target system's binaries, although at a prohibitively slow speed. The last time I tried, it was a matter of 8 hours vs 44 seconds. So we have the following cases: 0. primary arch 1. secondary arch that can run on native speeds 2. secondary arch that goes through qemu 3. secondary arch with no qemu enabled 4. non-multiarch cross compiler You are talking about the distinction between 0-2 vs 3-4, while there's a reason to avoid 2 if possible (yet it's more likely to succeed than 3). It'd be nice to specify the dependency in a way that doesn't make build-essential:armel prefer gcc:armel over gcc-armel-cross:amd64. Otherwise, I agree with you that multi-arch build-essential are so much better than cross-build-essential. > A note on terminology: in cross-compiling, the standard meaning of > "host" doesn't match how you used it. If I cross-compile a package for > armel on an i386 machine, armel is the "host architecture" and i386 is > the "build architecture". It's a terrible choice of names: outside of autotools world, everyone assumes that "host" is the architecture you're running the cross build on, hosting qemu on, etc. Kernel-like build systems for example print: HOSTCC something CC something This is the intuitive naming. > There is a third variable, "target", which is only used for compilers, > linkers and similar tools: to compile that package, I would have needed > a compiler built for an i386 "host architecture" with an armel "target > architecture". And outside of autotools, "target" is the target of your compilation. Confusion ensues. Too bad, I have no idea how to make it unambiguous. None of the three words is safe; even "build" would cause gems like BUILDCC which is unobvious at the very least. . That was qemu-system, I guess qemu-user would at least be able to use more than one core, and avoid a crippling memory limit. . And that's not even exhaustive. Just today, running "make clean" on something spawned a wine popup about updating some config, and the build log included: checking for suffix of executables... .exe checking whether we are cross-compiling... no -- Sanity is overrated anyway.
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