Update llvm-c headers for Version 11.0.1

src/llvm-c/TargetMachine.h

@@ -19,12 +19,12 @@
 #ifndef LLVM_C_TARGETMACHINE_H
 #define LLVM_C_TARGETMACHINE_H
 
+#include "ExternC.h"
 #include "Target.h"
 #include "Types.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
+LLVM_C_EXTERN_C_BEGIN
+
 typedef struct LLVMOpaqueTargetMachine *LLVMTargetMachineRef;
 typedef struct LLVMTarget *LLVMTargetRef;
 
@@ -156,8 +156,6 @@ char* LLVMGetHostCPUFeatures(void);
 /** Adds the target-specific analysis passes to the pass manager. */
 void LLVMAddAnalysisPasses(LLVMTargetMachineRef T, LLVMPassManagerRef PM);
 
-#ifdef __cplusplus
-}
-#endif
+LLVM_C_EXTERN_C_END
 
 #endif