[llvm] Revert [llvm] annotate ABIBreakingChecks symbols for DLL export (PR #147965)

[Andrew Rogers via llvm-commits]

https://github.com/andrurogerz created https://github.com/llvm/llvm-project/pull/147965

This patch reverts commit 24475409e4eac6fd60e2111424a4bef3452c8f21. The change introduced a cyclic dependency:
```
fatal error: cyclic dependency in module 'LLVM_Utils': LLVM_Utils -> LLVM_Config_ABI_Breaking -> LLVM_Utils
```

See failure log at https://green.lab.llvm.org/job/llvm.org/job/clang-stage2-Rthinlto/976/console.

>From 0f1b69bd5c01532671d9c3765d75dac6d2cd2d18 Mon Sep 17 00:00:00 2001
From: Andrew Rogers <andrurogerz at gmail.com>
Date: Thu, 10 Jul 2025 06:42:25 -0700
Subject: [PATCH] Revert "[llvm] annotate ABIBreakingChecks symbols for DLL
 export (#145575)"

This reverts commit 24475409e4eac6fd60e2111424a4bef3452c8f21.
---
 llvm/include/llvm/Config/abi-breaking.h.cmake | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/llvm/include/llvm/Config/abi-breaking.h.cmake b/llvm/include/llvm/Config/abi-breaking.h.cmake
index 318bd015f80d2..2d27e02b1d545 100644
--- a/llvm/include/llvm/Config/abi-breaking.h.cmake
+++ b/llvm/include/llvm/Config/abi-breaking.h.cmake
@@ -12,9 +12,6 @@
 #ifndef LLVM_ABI_BREAKING_CHECKS_H
 #define LLVM_ABI_BREAKING_CHECKS_H
 
-// Compiler.h is required for LLVM_ABI definition.
-#include "llvm/Support/Compiler.h"
-
 /* Define to enable checks that alter the LLVM C++ ABI */
 #cmakedefine01 LLVM_ENABLE_ABI_BREAKING_CHECKS
 
@@ -46,12 +43,12 @@
 #endif
 namespace llvm {
 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
-LLVM_ABI extern int EnableABIBreakingChecks;
+extern int EnableABIBreakingChecks;
 LLVM_HIDDEN_VISIBILITY
 __attribute__((weak)) int *VerifyEnableABIBreakingChecks =
     &EnableABIBreakingChecks;
 #else
-LLVM_ABI extern int DisableABIBreakingChecks;
+extern int DisableABIBreakingChecks;
 LLVM_HIDDEN_VISIBILITY
 __attribute__((weak)) int *VerifyDisableABIBreakingChecks =
     &DisableABIBreakingChecks;