Change the type of LLVM Message pointer to libc :: c_char

[ken109]

When I tried to install it on Ubuntu, I got the following error.

error[E0308]: mismatched types
  --> src/llvm/message.rs:34:36
   |
34 |                 LLVMDisposeMessage(self.ptr);
   |                                    ^^^^^^^^ expected `u8`, found `i8`
   |
   = note: expected raw pointer `*mut u8`
              found raw pointer `*mut i8`

error[E0308]: mismatched types
  --> src/llvm/message.rs:43:52
   |
43 |             let contents = unsafe { CStr::from_ptr(self.ptr).to_str().unwrap() };
   |                                                    ^^^^^^^^ expected `u8`, found `i8`
   |
   = note: expected raw pointer `*const u8`
              found raw pointer `*mut i8`

// Many others

The reason was that the arguments of LLVMDisposeMessage and LLVMCreateBinary are libc :: c_char type instead of i8 type.

[alessandrod]

Thank you and sorry for the wait! This slipped under my radar. See my comments.

[ken109]

@alessandrod
Fixed!

[alessandrod]

Thank you!