Don't require C bindings opcode numbers to be kept in sync.

They are not in sync now, for example Bitcast would show up as LLVMCall.
So instead introduce 2 functions that map to and from the opcodes in the C
bindings.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141290 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm-c/Core.h

@@ -179,8 +179,8 @@ typedef enum {
   LLVMPHI            = 44,
   LLVMCall           = 45,
   LLVMSelect         = 46,
-  /* UserOp1 */
-  /* UserOp2 */
+  LLVMUserOp1        = 47,
+  LLVMUserOp2        = 48,
   LLVMVAArg          = 49,
   LLVMExtractElement = 50,
   LLVMInsertElement  = 51,
@@ -195,7 +195,9 @@ typedef enum {
 
   /* Exception Handling Operators */
   LLVMResume         = 58,
-  LLVMLandingPad     = 59
+  LLVMLandingPad     = 59,
+  LLVMUnwind         = 60
+
 
 } LLVMOpcode;