Stripping binaries only partially implemented

[rgommers]

Related to gh-140. A check on the scipy 1.1.0rc1 wheels shows that _sparsetools.cpython-35m-x86_64-linux-gnu.so is now stripped (3.4 MB vs. previously 37 MB), however some other binaries are not:

$ ls -l cython_special.cpython-35m-x86_64-linux-gnu.so 
... 10694424 Apr 15 15:04 cython_special.cpython-35m-x86_64-linux-gnu.so
$ strip cython_special.cpython-35m-x86_64-linux-gnu.so 
$ ls -l cython_special.cpython-35m-x86_64-linux-gnu.so 
... 3065680 Apr 29 11:16 cython_special.cpython-35m-x86_64-linux-gnu.so
$ cd ../linalg
$ ls -l _flapack.cpython-35m-x86_64-linux-gnu.so 
... 3445392 Apr 15 15:04 _flapack.cpython-35m-x86_64-linux-gnu.so
$ strip _flapack.cpython-35m-x86_64-linux-gnu.so 
$ ls -l _flapack.cpython-35m-x86_64-linux-gnu.so 
... 1333960 Apr 29 11:17 _flapack.cpython-35m-x86_64-linux-gnu.so

Haven't investigated further yet, unclear to me if compiler flags aren't passed on or if they do something different than running strip afterwards.