We usually test against the newlib/libgloss environment, but for a
few ports that also support Linux apps, we want to test that logic
too. A lot of the C code is written such that it works with either
newlib/libgloss or glibc/linux toolchains, but we have some tests
that end up being Linux-specific. Cris has been using the target
tuple as a rough proxy for this (where cris*-*-elf is assumed to be
newlib/libgloss, and everything else is glibc/linux), but that is a
bit too rough, and it doesn't work in a multitarget build.
So lets create a few stub files that we can do compile tests with
to detect the different setups, and then let tests declare which
one they require (if they require any at all).
Now that all port tests live under testsuite/sim/*/, and none live
in testsuite/ directly, flatten the structure by moving all of the
dirs under testsuite/sim/ to testsuite/ directly.
We need to stop passing --tool to dejagnu so that it searches all
dirs and not just ones that start with "sim". Since we have no
other dirs in this tree, and no plans to add any, should be fine.