python - clang: error: unknown argument: '-mno-fused-madd' -

when installing reportlab 3.1.8, ran problem kept getting error , not find compiler option being set.

the point in setup was:

building 'reportlab.lib._rl_accel' extension

clang: error: unknown argument: '-mno-fused-madd' [-wunused-command-line-argument-hard-error-in-future] clang: note: hard error (cannot downgraded warning) in future error: command 'cc' failed exit status 1

here solution.

cause: keep mac date , result seems have newer (different) version of c compiler (clang) 1 allowed "-mno-fused-madd" command line switch.

solution: did not find above switch in file in reportlab source. had on computer itself. culprit seemed in distutils, because setup.py uses module distutils.

the problem in file /system/library/frameworks/python.framework/versions/2.7/lib/python2.7/_sysconfigdata.py. file contains definitions dictionary named build_time_vars. in right place have build time problem.

1. first make copy safeguard.
2. sudo <editor> <file path> edit file.
3. then editing file, search , remove switch -mno-fused-madd file. found in line beginning 'cflags' since compile flag. change line:

... -fwrapv -mno-fused-madd -denable_dtrace ... ... -fwrapv -denable_dtrace ...

save file , continue build. stay fixed. no need environment variables or such thing.

edit: while @ it, remove both _sysconfigdata.pyc , _sysconfigdata.pyo files.