test(library/rewriter): add lambda_rewrite tests
fix(library/rewriter): use Abst axiom in lambda_body RW
feat(util/stackinfo): implement get_stack_size (Mac OSX version)
fix(util/stackinfo): fix preprocessor directive
fix(util/stackinfo): fix typo
fix(util/stackinfo): handle error codes in the Linux version

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>