[www-scripts] Sphinx Doc Update: ERROR

[www-data via www-scripts]

/opt/tools/sphinx_update.sh: warning: removing stale lock file from PID 18967.
UPDATING lld SOURCES
Updating '.':
U    docs/WebAssembly.rst
U    wasm/SymbolTable.h
U    wasm/InputFiles.cpp
U    wasm/Driver.cpp
U    wasm/Symbols.h
U    wasm/LTO.cpp
U    wasm/Writer.cpp
U    wasm/SymbolTable.cpp
A    test/wasm/import-names.ll
U    test/wasm/cxx-mangling.ll
U    test/wasm/lto/weak-undefined.ll
U    test/wasm/archive-weak-undefined.ll
U    test/wasm/undefined-weak-call.ll
Updated to revision 353478.
-- Could NOT find Z3 (missing:  Z3_LIBRARIES Z3_INCLUDE_DIR) (Required is at least version "4.7.1")
CMake Error at cmake/modules/CheckCompilerVersion.cmake:40 (message):
  Host GCC version should be at least 5.1 because LLVM will soon use new C++
  features which your toolchain version doesn't support.  Your version is
  4.8.4.  You can temporarily opt out using
  LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN, but very soon your toolchain won't be
  supported.
Call Stack (most recent call first):
  cmake/modules/CheckCompilerVersion.cmake:45 (check_compiler_version)
  cmake/config-ix.cmake:13 (include)
  CMakeLists.txt:655 (include)


-- Configuring incomplete, errors occurred!
See also "/opt/sphinx-docs/build/llvm/CMakeFiles/CMakeOutput.log".
See also "/opt/sphinx-docs/build/llvm/CMakeFiles/CMakeError.log".
make[1]: *** [cmake_check_build_system] Error 1
make: *** [tools/lld/docs/CMakeFiles/docs-lld-html.dir/rule] Error 2