[chapel-lang/chapel] Fix problems with about prediff for --llvm test co

Branch: refs/heads/master
Revision: 420a262
Author: mppf
Log Message:

Merge pull request #16272 from mppf/fix-about-llvm

Fix problems with about prediff for --llvm test configs

Modified Files:
M test/execflags/sungeun/about.prediff

Compare: https://github.com/chapel-lang/chapel/compare/f1cafb8fc3e6...420a262feb9d