makepkg.conf: drop -fvar-tracking-assignments flag

According to gcc(1), this flag (like -fvar-tracking) is enabled by default when compiling with optimization and debugging information.

As an additional benefit, packages building with the clang compiler will work with the default flags without having to remove this flag due to not being recognized by clang.

requested review from @anthraxx

@allan What do you think (as the original committer of this flag)? ️

This was not the default when the flag was added, but given that has changed it can be dropped (and from the pacman package too). I'm not even sure it does much now GCC uses DWARF5.

approved this merge request

assigned to @anthraxx

added scopeenhancement label

merged

Also removed from pacman/trunk/makepkg.conf, pending the next pacman release.