const char* for LLVMTargetMachineEmitToFile's argument

[Tachyon]

Summary

The LLVMTargetMachineEmitToFile takes a char* Filename right now, but it doesn't modify it.
This is annoying to use in the case where you want to pass a const string, because you either have to remove the const, or copy it somewhere else and pass that. Either way, it's not very nice.

I added a const and clang formatted it. This shouldn't break any ABI in my opinion.
I'm sorry but I didn't know whom to put as reviewer for this, so I chose someone with a lot of commits from the .cpp file.

[Tachyon]

I don't know what I can do about the timeouts. If anyone could tell me, that'd be great.

[Tachyon]

Thanks for the accept. I don't have commit rights so if you could land it for me with "Andrei Damian <[e-mail]>" that would be great.

[deadalnix]

I will land this for you, no problem.

llvm/include/llvm-c/TargetMachine.h

 /** Set the target machine's ASM verbosity. */
 void LLVMSetTargetMachineAsmVerbosity(LLVMTargetMachineRef T,
                                       LLVMBool VerboseAsm);
 
 /** Emits an asm or object file for the given module to the filename. This
   wraps several c++ only classes (among them a file stream). Returns any
   error in ErrorMessage. Use LLVMDisposeMessage to dispose the message. */
 LLVMBool LLVMTargetMachineEmitToFile(LLVMTargetMachineRef T, LLVMModuleRef M,
-  char *Filename, LLVMCodeGenFileType codegen, char **ErrorMessage);
+                                     const char *Filename,
+                                     LLVMCodeGenFileType codegen,
+                                     char **ErrorMessage);
 
 /** Compile the LLVM IR stored in \p M and store the result in \p OutMemBuf. */
 LLVMBool LLVMTargetMachineEmitToMemoryBuffer(LLVMTargetMachineRef T, LLVMModuleRef M,
   LLVMCodeGenFileType codegen, char** ErrorMessage, LLVMMemoryBufferRef *OutMemBuf);
 
 /*===-- Triple ------------------------------------------------------------===*/
 /** Get a triple for the host machine as a string. The result needs to be
   disposed with LLVMDisposeMessage. */

llvm/lib/Target/TargetMachineC.cpp

static LLVMBool LLVMTargetMachineEmit(LLVMTargetMachineRef T, LLVMModuleRef M,
 
   pass.run(*Mod);
 
   OS.flush();
   return false;
 }
 
 LLVMBool LLVMTargetMachineEmitToFile(LLVMTargetMachineRef T, LLVMModuleRef M,
-  char* Filename, LLVMCodeGenFileType codegen, char** ErrorMessage) {
+                                     const char *Filename,
+                                     LLVMCodeGenFileType codegen,
+                                     char **ErrorMessage) {
   std::error_code EC;
   raw_fd_ostream dest(Filename, EC, sys::fs::OF_None);
   if (EC) {
     *ErrorMessage = strdup(EC.message().c_str());
     return true;
   }
   bool Result = LLVMTargetMachineEmit(T, M, dest, codegen, ErrorMessage);
   dest.flush();