[BPF] Allow selectively disable compiler builtins for BPF target#4

Merged

dmakarov merged 2 commits intoanza-xyz:solana-rustc/10.0-2020-05-05from

dmakarov:solana-rustc/10.0-2020-05-05

Feb 17, 2021

Commits on Feb 17, 2021

[BPF] Add method to check whether a triple is a BPF architecture
dmakarov
committed
[BPF] Make rust allocation builtins unavailable for BPF target
dmakarov
committed