[PATCH] Update mtoc installation guide for Xcode

[Roman Bolshakov <roolebo@gmail.com>]

mtoc was added to homebrew in Homebrew/homebrew-core#51730 and can be
installed on Catalina, Mojave and High Sierra.

Signed-off-by: Roman Bolshakov <roolebo@gmail.com>
---

Hello,

The patch is intended for tianocore github wiki that has restricted
editing for project members, that's why I'm sending it here.

If someone is using macOS, could you please verify that EFI built with
mtoc from homebrew works as expected.

Thank you,
Roman

 Xcode.md | 47 +----------------------------------------------
 1 file changed, 1 insertion(+), 46 deletions(-)

diff --git a/Xcode.md b/Xcode.md
index dc7e9fbb..0377fe44 100644
--- a/Xcode.md
+++ b/Xcode.md
@@ -17,53 +17,8 @@ While Xcode provides a full development environment as well as a suite of differ
 The mtoc utility is required to convert from the macOS Mach-O image format to the PE/COFF format as required by the UEFI specification.
 
 ### Brew Instructions
-Brew does not have an inbuilt version of mtoc so you must create it from source
-
-Go to http://www.opensource.apple.com/ and click on the latest open source version of the developer tools (currently 8.2.1) and you will get a list of projects that can be downloaded. 
-
-* Download the cctools project (currently cctools-895). 
-* Expand the tar file (double click on it in Finder)
-* Open a Terminal window to get a command line prompt.
-
-To build `mtoc` you will need to copy an include directory from the LLVM project.
-
-* Download http://llvm.org/releases/download.html#4.0
-* Copy the include/llvm-c and include/llvm directories from LLVM into the cctools include directory, but do not overwrite include/llvm-c/Disassembler.h.
-
-  ```
-  $ cp cctools-895/include/llvm-c/Disassembler.h .
-  $ cp -R llvm-4.0.0.src/include/llvm cctools-895/include/llvm
-  $ cp -R llvm-4.0.0.src/include/llvm-c cctools-895/include/llvm-c
-  $ cp Disassembler.h cctools-895/include/llvm-c
-  ```
-
-Then from the top cctools directory type:
-
-```
-$ cd cctools-895
-$ make
-```
-
-The make will finish with an error message on the file `strip.c`. This is expected. Then do the following:
-
-```
-$ cd efitools
-$ make
-```
-
-You have now built the command line application `mtoc.NEW`! Move it to a more useful location. 
-
-```
-$ sudo cp mtoc.NEW /usr/local/bin/mtoc
-```
-
-If this fails you probably don't have a local/bin directory under /usr. You need to add the directories by hand 
-
 ```
-$ cd /usr
-$ sudo mkdir local
-$ cd local
-$ sudo mkdir bin 
+$ brew install mtoc
 ```
 ## MacPorts Instructions
 ```