[arch-projects] [devtools] conf files could be closer to pacman's

[james harvey]

It could be worth a developer diff'ing:
* pacman::makepkg.conf and devtools::makepkg-x86_64.conf
* pacman::pacman.conf and devtools::pacman*.conf

When trying to figure out my /etc/ vs /usr/share/devtools/ confusion
with MAKEFLAGS, I saw these differ in more areas than I would have
expected.

I don't know if any of the differences matter in the end, but I think
it's nice they almost match, and I think it would be nicer if they
only differ in areas where they need to.

They probably used to match better, and diverged in a few areas where
they didn't need to.

Some of the differences are certainly nitpicky.  pacman just dropped
"-fstack-protector-strong" since it's enabled by default.
https://bugs.archlinux.org/task/54736

Others might matter in some situations, like different options on
DLAGENTS.  (I'm assuming it's right to have file:// missing from
devtools, talkinga bout the curl options.)

devtools gives package options "!optipng !upx".

devtools has a different comment for XferCommand and IgnorePkg.

Stuff like that.