[llvm] [llvm-c] Improve TargetMachine bindings (PR #70806)

[Mehdi Amini via llvm-commits]

================
@@ -175,6 +175,40 @@ void LLVMSetTargetMachineAsmVerbosity(LLVMTargetMachineRef T,
   unwrap(T)->Options.MCOptions.AsmVerbose = VerboseAsm;
 }
 
+void LLVMSetTargetMachineFastISel(LLVMTargetMachineRef T, LLVMBool Enable) {
+  unwrap(T)->setFastISel(Enable);
+}
+
+void LLVMSetTargetMachineGlobalISel(LLVMTargetMachineRef T, LLVMBool Enable) {
+  unwrap(T)->setGlobalISel(Enable);
+}
+
+void LLVMSetTargetMachineGlobalISelAbort(LLVMTargetMachineRef T,
+                                         LLVMGlobalISelAbortMode Mode) {
+  GlobalISelAbortMode AM;
+  switch (Mode) {
+  case LLVMGlobalISelAbortDisable:
+    AM = GlobalISelAbortMode::Disable;
+    break;
+  case LLVMGlobalISelAbortEnable:
+    AM = GlobalISelAbortMode::Enable;
+    break;
+  case LLVMGlobalISelAbortDisableWithDiag:
+    AM = GlobalISelAbortMode::DisableWithDiag;
+    break;
+  default:
+    AM = GlobalISelAbortMode::Enable;
----------------
joker-eph wrote:

This triggers a compiler warning:
```
llvm/lib/Target/TargetMachineC.cpp:276:3: warning: default label in switch which covers all enumeration values [-Wcovered-switch-default]
```

https://github.com/llvm/llvm-project/pull/70806