RSB uses hard coded GCC binary paths

[Sebastian Huber]

In order to build a tool chain with Ada support you need a native GCC with Ada support of the same version as the cross compiler. The RSB uses hard coded paths for the gcc and g++ programs:

source-builder/defaults.mc:__cc:                exe,     required, '/usr/bin/gcc'
source-builder/defaults.mc:__cxx:               exe,     required, '/usr/bin/g++'

So, the RSB user must change the main GCC installation of the machine to build a particular RTEMS tool chain. This is undesired/infeasible in most situations.

[Chris Johns]

I am OK with changing this to 'gcc' and 'g++'. There are a few other paths that could be relaxed, ie I remembering seeing something in your build logs.

This is something that has appeared as the RSB ages.

[Sebastian Huber <sebastian.huber@…>]

In 2a5c9da/rtems-source-builder:

Avoid hard coded GCC binary paths

In order to build a tool chain with Ada support a native GCC with Ada
support of the same version as the cross compiler is required. The RSB
used hard coded paths for the gcc and g++ programs. This forced the RSB
user to change the main GCC installation of the machine to build a
particular RTEMS tool chain. This is undesired/infeasible in most
situations.

Close #3284.