The brp-llvm-compile-lto-elf script uses PCRE in grep to match
for the -flto flag in bitcode object dumps, using negative
lookahead to exclude the case where -fno-lto is specified after.
When lines in the bitcode dump exceed the length that PCRE can
match against, grep will error out causing brp-llvm-compile-lto-elf
to fail.
This script implements an equivalent regex match in python to avoid
the limit in PCRE grep.
Resolves: rhbz#2017193
