Merge branch 'bug/make' into 'master'

真是受够了这个 libgit2 的问题

core依赖libgit2-v0.23.4，然而手动编译搞来搞去要么提示头文件找不到要么提示动态链接库找不到（哪怕我给了 `-DCMAKE_INSTALL_PREFIX=/usr/local/lib` ）

用 git apply 强行让brew回滚版本。。发现还挺好用的，于是推荐一下这种手段，在回滚版本的同时不会把自己的开发环境搞得脏兮兮的。

@platform

See merge request !21

Author: timfeirg

README.md

@@ -5,39 +5,10 @@ Core
 We use v0.23.4 because v0.24 sucks
 
 ```shell
-$ wget https://github.com/libgit2/libgit2/archive/v0.23.4.zip
-$ unzip v0.23.4.zip
-```
-Install dependencies: `libssh2`, `http-parser`, `cmake`, `libcurl`.
-
-```shell
-On Mac OSX:
-$ brew install libssh2 http-parser cmake libcurl
-
-On CentOS:
-$ yum install libssh2-devel http-parser cmake libcurl-devel
-```
-Then install libgit2.
-
-```shell
-$ cmake .  -DCMAKE_VERBOSE_MAKEFILE=ON -Wno-dev -DUSE_SSH=YES
-$ make && make install
-```
-Note on Mac OSX may need to set CFLAGS="-std=c99".
-Now libgit2 is installed under `/usr/local/lib` as default. We still need to set pkg-config and link dynamic libraries.
-
-```shell
-On Mac OSX:
-$ cd /usr/local/lib/pkgconfig
-$ ln -s /path/to/libgit2/pkgconfig/libgit2.pc  libgit2.pc
-$ cd /usr/local/lib
-$ ln -s /path/to/libgit2/libgit2.23.dylib libgit2.23.dylib
-
-On CentOS:
-$ cd /usr/lib64/pkgconfig/
-$ ln -s /usr/local/lib/pkgconfig/libgit2.pc libgit2.pc
-$ cd /usr/lib64
-$ ln -s /usr/local/lib/libgit2.so.23 libgit2.so.23
+cp devtools/libgit2.rb.patch /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Formula
+cd  /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Formula
+git apply libgit2.rb.patch && git add libgit2.rb && git commit -m "patch libgit2 version for eru-core" && rm libgit2.rb.patch
+cd -
 ```
 
 ## setup dev environment

devtools/libgit2.rb.patch

@@ -0,0 +1,15 @@
+diff --git a/Formula/libgit2.rb b/Formula/libgit2.rb
+index b91f4ff..45205f1 100644
+--- a/Formula/libgit2.rb
++++ b/Formula/libgit2.rb
+@@ -1,8 +1,8 @@
+ class Libgit2 < Formula
+   desc "C library of Git core methods that is re-entrant and linkable"
+   homepage "https://libgit2.github.com/"
+-  url "https://github.com/libgit2/libgit2/archive/v0.24.2.tar.gz"
+-  sha256 "00f0a7403143fba69601accc80cacf49becc568b890ba232f300c1b2a37475e6"
++  url "https://github.com/libgit2/libgit2/archive/v0.23.4.tar.gz"
++  sha256 "c7f5e2d7381dbc4d7e878013d14f9993ae8a41bd23f032718e39ffba57894029"
+   head "https://github.com/libgit2/libgit2.git"
+ 
+   bottle do