Make LLVM_ENABLE_CRASH_DUMPS set a variable default

That way users can set the default to true, but then disable core dumps
from certain apps that link support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@340588 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed