Revert "Add link-time detection of LLVM_ABI_BREAKING_CHECKS mismatch"

This reverts commit r287352, LLDB CI is broken.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287374 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/Error.cpp

@@ -112,19 +112,3 @@ void report_fatal_error(Error Err, bool GenCrashDiag) {
 }
 
 }
-
-
-#ifndef _MSC_VER
-namespace llvm {
-
-// One of these two variables will be referenced by a symbol defined in
-// llvm-config.h. We provide a link-time (or load time for DSO) failure when
-// there is a mismatch in the build configuration of the API client and LLVM.
-#if LLVM_ENABLE_ABI_BREAKING_CHECKS
-int EnableABIBreakingChecks;
-#else
-int DisableABIBreakingChecks;
-#endif
-
-} // end namespace llvm
-#endif