[SystemZ/ZOS] Add header file to encapsulate use of <sysexits.h>

The non-standard header file `<sysexits.h>` provides some return values.
`EX_IOERR` is used to as a special value to signal a broken pipe to the clang driver.
On z/OS Unix System Services, this header file does not exists. This patch

- adds a check for `<sysexits.h>`, removing the dependency on `LLVM_ON_UNIX`
- adds a new header file `llvm/Support/ExitCodes`, which either includes
  `<sysexits.h>` or defines `EX_IOERR`
- updates the users of `EX_IOERR` to include the new header file

Reviewed By: hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D83472

1 files changed, 1 insertions, 3 deletions

diff --git a/llvm/lib/Support/CrashRecoveryContext.cpp b/llvm/lib/Support/CrashRecoveryContext.cpp
index ec7d7d6..d4fd821 100644
--- a/llvm/lib/Support/CrashRecoveryContext.cpp
+++ b/llvm/lib/Support/CrashRecoveryContext.cpp
@@ -9,14 +9,12 @@
 #include "llvm/Support/CrashRecoveryContext.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/ExitCodes.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/ThreadLocal.h"
 #include <mutex>
 #include <setjmp.h>
-#if LLVM_ON_UNIX
-#include <sysexits.h> // EX_IOERR
-#endif
 
 using namespace llvm;