Omitting the first branch in ?: is a GNU extension. Cute,
but not supported by other compilers. Replaced mostly
by explicit tests. Calls to getenv() simply are repeated
on non-GNU compilers.
Signed-off-by: Jason Riedy <ejr@cs.berkeley.edu>
git_mkstemp() attempted to use TMPDIR environment variable, but it botched
copying the templates.
[jc: Holger, please add your own Signed-off-by line, and also if you can,
send in future patches as non attachments.]
Signed-off-by: Junio C Hamano <junkio@cox.net>