[docs] Add cmake to Software requirements

Add cmake to the list of packages required for compiling LLVM.
Also move make to the bottom of the list and mark it as optional.

Differential Revision: https://reviews.llvm.org/D65438

llvm-svn: 367395
diff --git a/llvm/docs/GettingStarted.rst b/llvm/docs/GettingStarted.rst
index 5f95095..9825e84 100644
--- a/llvm/docs/GettingStarted.rst
+++ b/llvm/docs/GettingStarted.rst
@@ -169,10 +169,11 @@
 =========================================================== ============ ==========================================
 Package                                                     Version      Notes
 =========================================================== ============ ==========================================
-`GNU Make <http://savannah.gnu.org/projects/make>`_         3.79, 3.79.1 Makefile/build processor
+`CMake <http://cmake.org/>`_                                >=3.4.3      Makefile/workspace generator
 `GCC <http://gcc.gnu.org/>`_                                >=5.1.0      C/C++ compiler\ :sup:`1`
 `python <http://www.python.org/>`_                          >=2.7        Automated test suite\ :sup:`2`
 `zlib <http://zlib.net>`_                                   >=1.2.3.4    Compression library\ :sup:`3`
+`GNU Make <http://savannah.gnu.org/projects/make>`_         3.79, 3.79.1 Makefile/build processor\ :sup:`4`
 =========================================================== ============ ==========================================
 
 .. note::
@@ -184,6 +185,7 @@
       ``llvm/test`` directory.
    #. Optional, adds compression / uncompression capabilities to selected LLVM
       tools.
+   #. Optional, you can use any other build tool supported by CMake.
 
 Additionally, your compilation host is expected to have the usual plethora of
 Unix utilities. Specifically: