A lot of modules that have nothing to do with git-shell functionality
were linked in, bloating git-shell more than 8 times.
This patch cuts off redundant dependencies by:
1. providing stubs for three functions that make no sense for git-shell;
2. moving quote_path_fully from environment.c to quote.c to make the
later self sufficient;
3. moving make_absolute_path into a new separate file.
The following numbers have been received with the default optimization
settings on master using GCC 4.1.2:
Before:
text data bss dec hex filename
143915 1348 93168 238431 3a35f git-shell
After:
text data bss dec hex filename
17670 788 8232 26690 6842 git-shell
Signed-off-by: Junio C Hamano <gitster@pobox.com>
