debListParser: Cache `essential` and `myArch` more

Lookup these variables in the constructor once, rather than
once per package.

This requires a bit of care as debListParser::UsePackage()
defaults to "all" for essential when unset, hence we simply
change its == "all" comparisons to == "all" || .empty().#

This removes any per-paragraph configuration lookups
from the file parser.

Also parse myArch from ParseProvides down to ParseDepends()
as that call ended up causing it to query APT::Architecture
*again* since the function we call is static.

Together, the removed config lookups safe about 2.3% of
cache generation runtime.

0 files changed, 0 insertions, 0 deletions