[all-commits] [llvm/llvm-project] e6c7ed: build: make `LLVM_ENABLE_ZLIB` a tri-bool for users

[Saleem Abdulrasool via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: e6c7ed6d2164a0659fd9f6ee44f1375d301e3cad
      https://github.com/llvm/llvm-project/commit/e6c7ed6d2164a0659fd9f6ee44f1375d301e3cad
  Author: Saleem Abdulrasool <compnerd at compnerd.org>
  Date:   2020-01-01 (Wed, 01 Jan 2020)

  Changed paths:
    M llvm/CMakeLists.txt
    M llvm/cmake/config-ix.cmake
    M llvm/lib/Support/CMakeLists.txt

  Log Message:
  -----------
  build: make `LLVM_ENABLE_ZLIB` a tri-bool for users

Treat the flag `LLVM_ENABLE_ZLIB` as a tri-bool, `FORCE_ON` being `ON`,
and `ON` being an auto-detect.  This is needed as many of the builders
enable the flag without having zlib available.