Unable to run cmake command

I followed the build guide, but I am not able to run cmake command
```
$ git clone https://github.com/llvm/llvm-project.git
Cloning into 'llvm-project'...
remote: Enumerating objects: 19852, done.
remote: Counting objects: 100% (19852/19852), done.
remote: Compressing objects: 100% (2966/2966), done.
remote: Total 3783698 (delta 19443), reused 16893 (delta 16886), pack-reused 3763846
Receiving objects: 100% (3783698/3783698), 826.68 MiB | 1.16 MiB/s, done.
Resolving deltas: 100% (3059690/3059690), done.
Checking out files: 100% (88978/88978), done.
$ cd llvm-project/
$ mkdir build
$ cd build/
$ cmake -G Ninja ../llvm
CMake Error: CMake was unable to find a build program corresponding to "Ninja". CMAKE_MAKE_PROGRAM is not set. You probably need to select a different build tool.
CMake Error: CMAKE_C_COMPILER not set, after EnableLanguage
CMake Error: CMAKE_CXX_COMPILER not set, after EnableLanguage
CMake Error: CMAKE_ASM_COMPILER not set, after EnableLanguage
-- Configuring incomplete, errors occurred!
See also "/home/mahmood/sources/llvm-project/build/CMakeFiles/CMakeOutput.log".
```

I also tried this command and it fails
```
$ cmake .. -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD=host -DLLVM_ENABLE_CXX1Y=ON -DLLVM_BUILD_TESTS=OFF -DLLVM_BINUTILS_INCDIR=~/codestitcher/source/binutils-2.30/include -DLLVM_BUILD_TOOLS=OFF -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++
CMake Error: The source directory "/storage/users/mnaderan/sources/llvm-project" does not appear to contain CMakeLists.txt.
Specify --help for usage, or press the help button on the CMake GUI.
```

Any way to fix that? What did I do wrong?