Harshits-Air:root harshitprasad$ cmake ../root
-- Found a Mac OS X System 10.13
-- Found a 64bit system
-- Found LLVM compiler collection
-- ROOT Platform: macosx
-- ROOT Architecture: macosx64
-- Build Type: RelWithDebInfo
-- Compiler Flags:  -Wc++11-narrowing -Wsign-compare -Wsometimes-uninitialized -Wconditional-uninitialized -Wheader-guard -Warray-bounds -Wcomment -Wtautological-compare -Wstrncat-size -Wloop-analysis -Wbool-conversion -m64 -pipe -W -Wshadow -Wall -Woverloaded-virtual -fsigned-char -fno-common -Qunused-arguments -pthread -std=c++11 -stdlib=libc++ -O2 -g -DNDEBUG
CMake Error at cmake/modules/RootNewMacros.cmake:1041 (message):
  ROOT should be built as an out of source build, to keep the source
  directory clean.  Please create a extra build directory and run the command
  'cmake <path_to_source_dir>' in this newly created directory.  You have
  also to delete the directory CMakeFiles and the file CMakeCache.txt in the
  source directory.  Otherwise cmake will complain even if you run it from an
  out-of-source directory.
Call Stack (most recent call first):
  CMakeLists.txt:107 (ROOT_CHECK_OUT_OF_SOURCE_BUILD)

cd ..
mkdir build
cd build
cmake ../root