rpcs3 cmake error

sorry, it did not work

git submodule update --init
fatal: Not a git repository (or any of the parent directories): .git

and

cmake CMakeLists.txt
-- cotire 1.6.1 loaded.
-- Initializing RPCS3_SRC_DIR=/root/Downloads/rpcs3-master/rpcs3
CMake Error at CMakeLists.txt:76 (find_package):
Could not find a package configuration file provided by "LLVM" with any of
the following names:

LLVMConfig.cmake
llvm-config.cmake

Add the installation prefix of "LLVM" to CMAKE_PREFIX_PATH or set
"LLVM_DIR" to a directory containing one of the above files. If "LLVM"
provides a separate development package or SDK, be sure it has been
installed.


-- Configuring incomplete, errors occurred!

---

I have also tried:
git init
git submodule update
now it does not give me the error
and then

cmake CMakeLists.txt
-- cotire 1.6.1 loaded.
-- Initializing RPCS3_SRC_DIR=/root/Downloads/rpcs3-master/rpcs3
CMake Error at CMakeLists.txt:76 (find_package):
Could not find a package configuration file provided by "LLVM" with any of
the following names:

LLVMConfig.cmake
llvm-config.cmake

Add the installation prefix of "LLVM" to CMAKE_PREFIX_PATH or set
"LLVM_DIR" to a directory containing one of the above files. If "LLVM"
provides a separate development package or SDK, be sure it has been
installed.


-- Configuring incomplete, errors occurred!