[Feature request] Add gdb-multiarch

Description:

Add a package like Debian's gdb-multiarch, which supports all architectures.

Although users can install gdb for every architecture they need individually, but a gdb-multiarch reduces mess a lot!

This should be provided as another split package, which won't affect current gdb users. Only people who need gdb-multiarch will install it.

The AUR gdb-multiarch package can used as a PKGBUILD reference. And it has 25 votes and 1.13 popularity, which is much more than the 10 votes baseline.

Please consider this! Thanks!