python - pip install scipy using wrong architecture

Question

Doing a pip install scipy in a clean, empty virtualenv on an odroid XU4 (python 2.7, ubuntu 15.04)

uname -a

Linux odroid 3.10.82-57 #1 SMP PREEMPT Wed Oct 7 13:19:01 BRT 2015 armv7l armv7l armv7l GNU/Linux

output:

...
gfortran: error: unrecognized argument in option ‘-march=x86-64’
gfortran: note: valid arguments to ‘-march=’ are: armv2 armv2a armv3 armv3m armv4 armv4t armv5 armv5e armv5t armv5te armv6 armv6-m armv6j armv6k armv6s-m armv6t2 armv6z armv6zk armv7 armv7-a armv7-m armv7-r armv7e-m armv7ve armv8-a armv8-a+crc iwmmxt iwmmxt2 native
gfortran: error: unrecognized argument in option ‘-mtune=generic’
gfortran: note: valid arguments to ‘-mtune=’ are: arm1020e arm1020t arm1022e arm1026ej-s arm10e arm10tdmi arm1136j-s arm1136jf-s arm1156t2-s arm1156t2f-s arm1176jz-s arm1176jzf-s arm2 arm250 arm3 arm6 arm60 arm600 arm610 arm620 arm7 arm70 arm700 arm700i arm710 arm7100 arm710c arm710t arm720 arm720t arm740t arm7500 arm7500fe arm7d arm7di arm7dm arm7dmi arm7m arm7tdmi arm7tdmi-s arm8 arm810 arm9 arm920 arm920t arm922t arm926ej-s arm940t arm946e-s arm966e-s arm968e-s arm9e arm9tdmi cortex-a12 cortex-a15 cortex-a15.cortex-a7 cortex-a5 cortex-a53 cortex-a57 cortex-a57.cortex-a53 cortex-a7 cortex-a8 cortex-a9 cortex-m0 cortex-m0.small-multiply cortex-m0plus cortex-m0plus.small-multiply cortex-m1 cortex-m1.small-multiply cortex-m3 cortex-m4 cortex-m7 cortex-r4 cortex-r4f cortex-r5 cortex-r7 ep9312 fa526 fa606te fa626 fa626te fa726te fmp626 generic-armv7-a iwmmxt iwmmxt2 marvell-pj4 mpcore mpcorenovfp native strongarm strongarm110 strongarm1100 strongarm1110 xscale
gfortran: error: unrecognized command line option ‘-msse2’
gfortran: error: unrecognized argument in option ‘-march=x86-64’
gfortran: note: valid arguments to ‘-march=’ are: armv2 armv2a armv3 armv3m armv4 armv4t armv5 armv5e armv5t armv5te armv6 armv6-m armv6j armv6k armv6s-m armv6t2 armv6z armv6zk armv7 armv7-a armv7-m armv7-r armv7e-m armv7ve armv8-a armv8-a+crc iwmmxt iwmmxt2 native
gfortran: error: unrecognized argument in option ‘-mtune=generic’
gfortran: note: valid arguments to ‘-mtune=’ are: arm1020e arm1020t arm1022e arm1026ej-s arm10e arm10tdmi arm1136j-s arm1136jf-s arm1156t2-s arm1156t2f-s arm1176jz-s arm1176jzf-s arm2 arm250 arm3 arm6 arm60 arm600 arm610 arm620 arm7 arm70 arm700 arm700i arm710 arm7100 arm710c arm710t arm720 arm720t arm740t arm7500 arm7500fe arm7d arm7di arm7dm arm7dmi arm7m arm7tdmi arm7tdmi-s arm8 arm810 arm9 arm920 arm920t arm922t arm926ej-s arm940t arm946e-s arm966e-s arm968e-s arm9e arm9tdmi cortex-a12 cortex-a15 cortex-a15.cortex-a7 cortex-a5 cortex-a53 cortex-a57 cortex-a57.cortex-a53 cortex-a7 cortex-a8 cortex-a9 cortex-m0 cortex-m0.small-multiply cortex-m0plus cortex-m0plus.small-multiply cortex-m1 cortex-m1.small-multiply cortex-m3 cortex-m4 cortex-m7 cortex-r4 cortex-r4f cortex-r5 cortex-r7 ep9312 fa526 fa606te fa626 fa626te fa726te fmp626 generic-armv7-a iwmmxt iwmmxt2 marvell-pj4 mpcore mpcorenovfp native strongarm strongarm110 strongarm1100 strongarm1110 xscale
gfortran: error: unrecognized command line option ‘-msse2’
error: Command "/usr/bin/gfortran -Wall -g -ffixed-form -fno-second-underscore -fPIC -O2 -march=x86-64 -DMS_WIN64 -mtune=generic -msse2 -I/home/dgorissen/venvs/orangspy/local/lib/python2.7/site-packages/numpy/core/include -c -c scipy/fftpack/src/dfftpack/dcosti.f -o build/temp.linux-armv7l-2.7/scipy/fftpack/src/dfftpack/dcosti.o" failed with exit status 1
 ...

So obviously pip is not properly picking up its an arm. What is the correct way to set this?

I note that arm7l (as listed by uname) is not listed as an option in the error trace above but tried it anyway as follows:

ARCHFLAGS='-arch arm7l' pip install scipy

But the exact same output.

I know I can apt-get install python-scipy but Id rather do it via pip so I can use the latest version and have full control over my environment (debugging an issue where the ubuntu packaged scipy just hangs on certain functions which run fine on x64)

Edit: Tried compiling directly from source per instructions here, but still the same problem, gfortran not picking up the right arch.