MC: Move ExceptionHandling enum to Support (#144692)

Similar to b5967264b0fbfd502b3a7edec27409e966fb68be, we need
to use this in RuntimeLibcalls to compute the set of library
calls.
diff --git a/llvm/include/llvm/MC/MCTargetOptions.h b/llvm/include/llvm/MC/MCTargetOptions.h
index 3ee21d9..d95adf9 100644
--- a/llvm/include/llvm/MC/MCTargetOptions.h
+++ b/llvm/include/llvm/MC/MCTargetOptions.h
@@ -10,6 +10,7 @@
 #define LLVM_MC_MCTARGETOPTIONS_H
 
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/Support/CodeGen.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Compression.h"
 #include <string>
@@ -17,18 +18,6 @@
 
 namespace llvm {
 
-enum class ExceptionHandling {
-  None,     ///< No exception support
-  DwarfCFI, ///< DWARF-like instruction based exceptions
-  SjLj,     ///< setjmp/longjmp based exceptions
-  ARM,      ///< ARM EHABI
-  WinEH,    ///< Windows Exception Handling
-  Wasm,     ///< WebAssembly Exception Handling
-  AIX,      ///< AIX Exception Handling
-  ZOS,      ///< z/OS MVS Exception Handling. Very similar to DwarfCFI, but the PPA1
-            ///< is used instead of an .eh_frame section.
-};
-
 enum class EmitDwarfUnwindType {
   Always,          // Always emit dwarf unwind
   NoCompactUnwind, // Only emit if compact unwind isn't available
diff --git a/llvm/include/llvm/Support/CodeGen.h b/llvm/include/llvm/Support/CodeGen.h
index 90733b5..cd1f916 100644
--- a/llvm/include/llvm/Support/CodeGen.h
+++ b/llvm/include/llvm/Support/CodeGen.h
@@ -50,6 +50,18 @@
     };
   }
 
+  enum class ExceptionHandling {
+    None,     ///< No exception support
+    DwarfCFI, ///< DWARF-like instruction based exceptions
+    SjLj,     ///< setjmp/longjmp based exceptions
+    ARM,      ///< ARM EHABI
+    WinEH,    ///< Windows Exception Handling
+    Wasm,     ///< WebAssembly Exception Handling
+    AIX,      ///< AIX Exception Handling
+    ZOS, ///< z/OS MVS Exception Handling. Very similar to DwarfCFI, but the
+         ///< PPA1 is used instead of an .eh_frame section.
+  };
+
   namespace FloatABI {
   enum ABIType {
     Default, // Target-specific (either soft or hard depending on triple, etc).