[ARROW-4407] [C++] ExternalProject_Add does not capture CC/CXX correctly

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.12.0
• Fix Version/s: 0.13.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/20970
• Assignee: Francois Saint-Jacques
• Reporter: Francois Saint-Jacques
• Created: 28/Jan/19 18:43
• Updated: 11/Jan/23 07:33
• Resolved: 30/Jan/19 21:25

Description

The issue is that CC/CXX environment variables are captured on the first invocation of the builder (e.g make or ninja) instead of when CMake is invoked into to build directory. This can lead to compilation errors (notably when compiling with clang in the top directory due to the addition of the `-Qunused-arguments` option).

This leads to an issue where I have a script that prepare the build directory and export CXX within the script. When I jump in the build folder, there's a mismatch between the external gbenchmark (and all deps if conda is not used) compiler and the build.

To reproduce:

1. Create a new build directory with clang as compiler, don't build yet
2. In a new shell (without the compiler environment variable), go into directory invoke make/ninja

Issue Links

• links to: GitHub Pull Request #3515