zephyr-env.sh: Fixed sourcing the project environment file

In zsh the value of $0 depends on the FUNCTION_ARGZERO option
which is set by default. FUNCTION_ARGZERO, when it is set, sets
$0 temporarily to the name of the function/script when executing
a shell function or sourcing a script. POSIX_ARGZERO option,
when it is set, exposes the original value of $0 in spite of the
current FUNCTION_ARGZERO setting.

This patch allows to source the project environment file from
both zsh and bash. It also removes the -z option from the
basename command which is missing in OS X.

Change-Id: I5a32404784d9064bf749fa58b4d73d4b56c908c2
Signed-off-by: Yannis Damigos <giannis.damigos@gmail.com>
1 file changed