build on armv7l fails

[rngadam]

can modify:

is_arm = machine in ['aarch64', 'aarch64_be', 'armv8b', 'armv8l']

to add armv7l.

However, this still tries to compile src/smhasher/metrohash64crc.cpp which apparently relies on i386 64-bit code:

/home/ubuntu/build/buildroot-2019.11.1/output/host/bin/arm-buildroot-linux-gnueabihf-gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -fPIC -c src/smhasher/metrohash64crc.cpp -o build/temp.linux-armv7l-3.8/src/smhasher/metrohash64crc.o -mfloat-abi=hard -march=armv7-a -mfpu=neon
    src/smhasher/metrohash64crc.cpp:28:10: fatal error: nmmintrin.h: No such file or directory
     #include <nmmintrin.h>
              ^~~~~~~~~~~~~
    compilation terminated.
    error: command '/home/ubuntu/build/buildroot-2019.11.1/output/host/bin/arm-buildroot-linux-gnueabihf-gcc' failed with exit status 1
    ----------------------------------------

nmmintrin.h seems to be containing specific optimizations for i386

[rngadam]

sorry for the confusion, I opened the issue in pyhash instead:

flier/pyfasthash#40