Bug#912566: sparse FTBFS with llvm/clang 7

[Sylvestre Ledru]

reassign 912566 sparse
forwarded 912566 https://bugs.llvm.org/show_bug.cgi?id=8220
thanks

Hello
This is because llvm-config isn't great (understatement).
It inherits of the flags used to compile llvm.

See also:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=697755

I proposed this MR to address that:
https://salsa.debian.org/ukleinek/sparse/merge_requests/1

Cheers,
Sylvestre