error compiling webassembly in Debian

rafa@genia:~/emsdk$ ./emsdk install –build=Release sdk-incoming-64bit binaryen-master-64bit
Installing SDK ‘sdk-incoming-64bit’..
Installing tool ‘clang-incoming-64bit’..
Cloning into ‘/home/rafa/emsdk/clang/fastcomp/src’…
remote: Counting objects: 1475072, done.
remote: Compressing objects: 100% (3/3), done.
remote: Total 1475072 (delta 1), reused 6 (delta 1), pack-reused 1475066
Receiving objects: 100% (1475072/1475072), 343.96 MiB | 888.00 KiB/s, done.
Resolving deltas: 100% (1219010/1219010), done.
Checking out files: 100% (28635/28635), done.
Fetching latest changes to the branch ‘incoming’ for ‘/home/rafa/emsdk/clang/fastcomp/src’…
Already up-to-date.
Successfully updated and checked out branch ‘incoming’ on repository ‘/home/rafa/emsdk/clang/fastcomp/src’
Current repository version: “Mon, 4 Jun 2018 13:29:55 -0700 cd96346a22e2bcff45f8605a1798ce59f9068029”
Cloning into ‘/home/rafa/emsdk/clang/fastcomp/src/tools/clang’…
remote: Counting objects: 663281, done.
remote: Compressing objects: 100% (5331/5331), done.
remote: Total 663281 (delta 18746), reused 21989 (delta 18380), pack-reused 639462
Receiving objects: 100% (663281/663281), 149.45 MiB | 985.00 KiB/s, done.
Resolving deltas: 100% (560849/560849), done.
Checking out files: 100% (15015/15015), done.
Fetching latest changes to the branch ‘incoming’ for ‘/home/rafa/emsdk/clang/fastcomp/src/tools/clang’…
Already up-to-date.
Successfully updated and checked out branch ‘incoming’ on repository ‘/home/rafa/emsdk/clang/fastcomp/src/tools/clang’
Current repository version: “Mon, 4 Jun 2018 13:29:57 -0700 ca88c9c04a44f90584aa05686717498ed876ec86”
Running CMake: [‘cmake’, ‘-G’, ‘Unix Makefiles’, ‘-DCMAKE_BUILD_TYPE=Release’, ‘-DPYTHON_EXECUTABLE=/usr/bin/python’, ‘-DLLVM_TARGETS_TO_BUILD=X86;JSBackend’, ‘-DLLVM_INCLUDE_EXAMPLES=OFF’, ‘-DCLANG_INCLUDE_EXAMPLES=OFF’, ‘-DLLVM_INCLUDE_TESTS=OFF’, ‘-DCLANG_INCLUDE_TESTS=OFF’, ‘-DLLVM_ENABLE_ASSERTIONS=OFF’, ‘/home/rafa/emsdk/clang/fastcomp/src’]
— The C compiler identification is unknown
— The CXX compiler identification is GNU 6.3.0
— The ASM compiler identification is GNU
— Found assembler: /usr/bin/c++
CMake Error at CMakeLists.txt:45 (project):
No CMAKE_C_COMPILER could be found.

Tell CMake where to find the compiler by setting either the environment
variable “CC” or the CMake cache entry CMAKE_C_COMPILER to the full path to
the compiler, or to the compiler name if it is in the PATH.

— Check for working CXX compiler: /usr/bin/c++
— Check for working CXX compiler: /usr/bin/c++ — works
— Detecting CXX compiler ABI info
— Detecting CXX compiler ABI info – done
— Detecting CXX compile features
— Detecting CXX compile features – done
— Configuring incomplete, errors occurred!
See also “/home/rafa/emsdk/clang/fastcomp/build_incoming_64/CMakeFiles/CMakeOutput.log”.
See also “/home/rafa/emsdk/clang/fastcomp/build_incoming_64/CMakeFiles/CMakeError.log”.
CMake invocation failed due to exception!
Working directory: /home/rafa/emsdk/clang/fastcomp/build_incoming_64
Command ‘[‘cmake’, ‘-G’, ‘Unix Makefiles’, ‘-DCMAKE_BUILD_TYPE=Release’, ‘-DPYTHON_EXECUTABLE=/usr/bin/python’, ‘-DLLVM_TARGETS_TO_BUILD=X86;JSBackend’, ‘-DLLVM_INCLUDE_EXAMPLES=OFF’, ‘-DCLANG_INCLUDE_EXAMPLES=OFF’, ‘-DLLVM_INCLUDE_TESTS=OFF’, ‘-DCLANG_INCLUDE_TESTS=OFF’, ‘-DLLVM_ENABLE_ASSERTIONS=OFF’, ‘/home/rafa/emsdk/clang/fastcomp/src’]’ returned non-zero exit status 1
Installation failed!
rafa@genia:~/emsdk$