For example, for GCC/GCN target (AMD GPUs), target libraries are built
individually per supported hardware ISA ('-march=[...]'). Testing such a
toolchain via, for example:
$ make RUNTESTFLAGS='--target_board=[...]/-march=gfx90a' check[...]
... does work fine for all 'check-gcc-[...]' as well as GCC-provided target
libraries, 'check-target-[...]'. Just for 'check-target-newlib', for the
example above, not the '-march=gfx90a' newlib libraries are linked in, but
instead always the default ones, which results in link FAILure. This is cured
simply by skipping use of 'newlib/testsuite/lib/flags.exp', so that the
standard search paths as determined by GCC, DejaGnu are used for newlib, too.