Consider different C lib as "cross-compile"

[piranna]

• Version: since 7.0.0
• Platform: Linux slimbook-C16B 4.8.0-29-generic Updates README with IRC channel for #io.js #31-Ubuntu SMP Wed Nov 30 19:13:21 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
• Subsystem: compile process

I'm using an own cross-toolchain to compile Node.js using musl from a Ubuntu glib-based system. Thing is that I get always the next error:

/bin/sh: 1: /home/piranna/Proyectos/nodejs/deps/node/out/Release/mkpeephole: not found

The file is there, but since I'm using the cross-toolchain to compile Node.js, mkpeephole gets to be compiled with it too because I'm cross-compiling from LInux x86_64 GLib to Linux x86_64 musl, and at configure script it's only being considered the CPU architecture to detect if it's being done a cross-compilation. I would consider adding other heuristics to check if a cross-compilation is being done, specially the C standard lib being used but also the operating system and others, or alternatively add an option to set explicitly that a cross-compilation is being done.

[piranna]

I have found that the pull-request #10287 is not just enough, because the system libraries and headers are still needed to make the compilation successful. By default both ./configure and make are using the globally installed C/C++ compilers and there's no way to set an alternative toolchain or sysroot, so while up to Node.js 6.x it's just enough by executing ./configure setting the $CC and $CXX environment variables, now it doesn't work due to mkpeephole before it needs to be executed on the host system. I have found too that also some components of the final Node.js binary are being build with the global C/C++ compiler, so or I'm doing something totally wrong, or the Node.js cross-compilation support is plainly broken :-/