cmake/clang.cmake REGEX command on Debian 10

[zheka8]

When running ./020_build_vc4c.sh on Raspberry Pi 3B+ running Debian Buster the following error occurs:

 CMake Error at cmake/clang.cmake:23 (string):
  string sub-command REGEX, mode REPLACE needs at least 6 arguments total to
  command.
Call Stack (most recent call first):
  CMakeLists.txt:121 (include)

Solution is to inclose the last parameter of REGEX in cmake/clang.cmake:23 in quotes:

string (REGEX REPLACE ".*clang version ([0-9]+\\.[0-9]+).*" "\\1" CLANG_VERSION_STRING "${clang_full_version_string}")