title: Having difficulty to install git using Homebrew
body: <p>I am watching <a href="http://www.youtube.com/watch?v=WUviVWnvBM8" rel="nofollow">this video</a> to install git using Homebrew. I already got Homebrew installed. The problem i have is installing git using Homebrew. I typed brew install git and have certain error message.</p>
  
  <p>Error msg: </p>
  
  <pre><code>./generate-cmdlist.sh &gt; common-cmds.h+ &amp;&amp; mv common-cmds.h+ common-cmds.h
  /usr/bin/xcrun clang -o hex.o -c -MF ./.depend/hex.o.d -MMD -MP  -Os -w -pipe -march=native -Qunused-arguments -I. -DUSE_ST_TIMESPEC -DNO_GETTEXT  -DHAVE_DEV_TTY -DSHA1_HEADER='&lt;openssl/sha.h&gt;'  -DNO_MEMMEM  hex.c
  /usr/bin/xcrun clang -o ident.o -c -MF ./.depend/ident.o.d -MMD -MP  -Os -w -pipe -march=native -Qunused-arguments -I. -DUSE_ST_TIMESPEC -DNO_GETTEXT  -DHAVE_DEV_TTY -DSHA1_HEADER='&lt;openssl/sha.h&gt;'  -DNO_MEMMEM  ident.c
  /usr/bin/xcrun clang -o kwset.o -c -MF ./.depend/kwset.o.d -MMD -MP  -Os -w -pipe -march=native -Qunused-arguments -I. -DUSE_ST_TIMESPEC -DNO_GETTEXT  -DHAVE_DEV_TTY -DSHA1_HEADER='&lt;openssl/sha.h&gt;'  -DNO_MEMMEM  kwset.c
  In file included from ident.c:8:
  In file included from ./cache.h:4:
  ./git-compat-util.h:93:10: fatal error: 'unistd.h' file not found
  #include &lt;unistd.h&gt;
           ^
  In file included from hex.c:1:
  In file included from ./cache.h:4:
  ./git-compat-util.h:93:10: fatal error: 'unistd.h' file not found
  #include &lt;unistd.h&gt;
           ^
  In file included from kwset.c:37:
  In file included from ./cache.h:4:
  ./git-compat-util.h:93:10: fatal error: 'unistd.h' file not found
  #include &lt;unistd.h&gt;
           ^
  1 error generated.
  make: *** [hex.o] Error 1
  1 error generated.
  make: *** Waiting for unfinished jobs....
  make: *** [ident.o] Error 1
  1 error generated.
  make: *** [kwset.o] Error 1
  ==&gt; Build Environment
  CPU: quad-core 64-bit sandybridge
  MacOS: 10.7.4-x86_64
  Xcode: 4.3.2
  CC: /usr/bin/xcrun clang =&gt; /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang
  
  CXX: /usr/bin/xcrun clang++ =&gt; /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++
  
  LD: /usr/bin/xcrun clang =&gt; /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang
  
  CFLAGS: -Os -w -pipe -march=native -Qunused-arguments
  CXXFLAGS: -Os -w -pipe -march=native -Qunused-arguments
  MAKEFLAGS: -j4
  Error: Failed executing: make prefix=/usr/local/Cellar/git/1.7.10.3 CC=/usr/bin/xcrun\ clang CFLAGS=-Os\ -w\ -pipe\ -march=native\ -Qunused-arguments LDFLAGS= install (git.rb:49)
  These existing issues may help you:
      https://github.com/mxcl/homebrew/issues/8643
      https://github.com/mxcl/homebrew/issues/9023
      https://github.com/mxcl/homebrew/issues/9618
      https://github.com/mxcl/homebrew/issues/10544
      https://github.com/mxcl/homebrew/issues/11481
      https://github.com/mxcl/homebrew/issues/12325
      https://github.com/mxcl/homebrew/issues/12344
      https://github.com/mxcl/homebrew/issues/12400
      https://github.com/mxcl/homebrew/issues/12478
  Otherwise, please report the bug:
      https://github.com/mxcl/homebrew/wiki/reporting-bugs
  </code></pre>
  
  <p>How do i solve this error? Need some help</p>