Redmine #6215, #6220: Avoid Solaris ISA error because of fakeroot.

It boils down to certain tools being 64-bit, while fakeroot is 32-bit,
so the fakeroot library preload fails which causes further problems
later. Conveniently however, Solaris comes with alternate 32-bit
tools, we just need to know where to look for them. So specify these
alternate folders when looking for platform tools.