The multi-build.in file in libgloss duplicates common multilib logic
in the root source tree. Document it a bit, and rename the rule so
it doesn't clash with the common multi-do rule. This will let us use
them in the same makefile so we can merge aarch64/ & arm/ up (as the
only targets that use this local multi-build.in atm).
The previous multi-build implementation was copying the config.status from the parent
multilib directory when building the different semihosting variants. It did so because
the configuration doesn't change. However when you use a relative path to configure it
turns out that the paths inside the config.status are also relative.
To fix this, the srcdir is adjusted from the initial configuration instead of copying it.
Tested on aarch64-none-elf and arm-none-eabi.
Signed-off-by: Tamar Christina <tamar.christina@arm.com>
e.g. from the same source file produce multiple libs by varying the
options passed to the compiler.
Signed-off-by: Tamar Christina <tamar.christina@arm.com>