[Chapel Merge] Update LLVM and cmake prereqs

Branch: refs/heads/main
Revision: ba63a17
Author: mppf
Log Message:

Merge pull request #18390 from mppf/fix-cmake-prereqs

Update LLVM and cmake prereqs

This PR makes several updates to prereqs.rst:

  • updates the required cmake version to 3.4.3 (LLVM 11 requires this
    version) but mentions 3.13.4 (which will be required in LLVM 12 and
  • moves the description of the cmake requirement to the LLVM=bundled
  • updates the example commands to install dependencies to include LLVM 11
    and cmake

Reviewed by @daviditen - thanks!

Modified Files:
M doc/rst/usingchapel/prereqs.rst

Compare: https://github.com/chapel-lang/chapel/compare/ab1d90b09716...ba63a17b6d0a