Fixes quite a lot of brokenness when ident information needs to be taken
from the system and cleans up the code.
By Jeff King
* jk/ident-gecos-strbuf:
format-patch: refactor get_patch_filename
ident: trim whitespace from default name/email
ident: use a dynamic strbuf in fmt_ident
ident: use full dns names to generate email addresses
ident: report passwd errors with a more friendly message
drop length limitations on gecos-derived names and emails
ident: don't write fallback username into git_default_name
fmt_ident: drop IDENT_WARN_ON_NO_NAME code
format-patch: use default email for generating message ids
ident: trim trailing newline from /etc/mailname
move git_default_* variables to ident.c
move identity config parsing to ident.c
fmt-merge-msg: don't use static buffer in record_person
http-push: do not access git_default_email directly
ident: split setup_ident into separate functions
6fce81629b