On a Mac, encountering clang: error: unknown argument: '-mno-fused-madd' → Use ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future

$ pip install reportlab

After running this command

clang: error: unknown argument: '-mno-fused-madd' [-Wunused-command-line-argument-hard-error-in-future]
clang: note: this will be a hard error (cannot be downgraded to a warning) in the future
error: command 'cc' failed with exit status 1

I encountered this error.

It seems to occur during the installation of a dependency package (pillow?).

Fix 'clang: unknown argument' error after updating to Xcode 5.1

http://kaspermunck.github.io/2014/03/fixing-clang-error/

Referring to this page

ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future pip install reportlab