This patch, submitted upstream but not (yet?) accepted, adds a third
parameter to the specs file 'getenv' function that provides a value
for when the environment variable is not set, instead of having gcc
fail.
This seemed like the safest way to provide a mechanism for getting the
installed location of the toolchain from inside a specs file as, when
not installed in the built-in location, gcc already sets the
GCC_EXEC_PREFIX environment variable to a well defined location within
that directory hierarchy, but when installed in the location specified
at compile time, gcc does not. Providing a default value that matches
the compile-time location then allows the specs file to compute paths
relative to the current GCC installation location, whereever it is
installed.
Signed-off-by: Keith Packard <keithp@keithp.com>
