[www-scripts] Sphinx Doc Update: ERROR

[www-data via www-scripts]

/opt/tools/sphinx_update.sh: warning: removing stale lock file from PID 14076.
UPDATING llvm SOURCES
Updating '.':
U    docs/LibFuzzer.rst
Updated to revision 353551.
-- 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: *** [docs/CMakeFiles/docs-llvm-html.dir/rule] Error 2