[PATCH v2 0/2] Write DWARF index cache files in background

[Tom Tromey]

Here's v2 of the series to write the DWARF index cache file in the
background.

v1 is here:

    https://sourceware.org/pipermail/gdb-patches/2022-April/187844.html

This version is mostly just a rebase.

Regression tested on x86-64 Fedora 34.

Tom