Issue 1:
Building latest HEAD with Visual Studio 14.22.27905 (Visual Studio 2019 Community Edition) fails, there are warnings that are turned into an error:

_simd.dispatch.avx512_skx.c
numpy\core\src\_simd\_simd.dispatch.c.src(425):
warning C4244: 'initializing': conversion from '__mmask16' to 'npyv_b64', \
possible loss of data
... and 3 more like that

The warnings point to this code (the first SIMD_IMPL_INTRIN_2` is line 425):

// Logical
/**begin repeat
* #bsfx = b8, b16, b32, b64#
*/
SIMD_IMPL_INTRIN_2(and_@bsfx@, v@bsfx@, v@bsfx@, v@bsfx@)
SIMD_IMPL_INTRIN_2(or_@bsfx@, v@bsfx@, v@bsfx@, v@bsfx@)
SIMD_IMPL_INTRIN_2(xor_@bsfx@, v@bsfx@, v@bsfx@, v@bsfx@)
SIMD_IMPL_INTRIN_1(not_@bsfx@, v@bsfx@, v@bsfx@)

It seems the first line is preprocessed into (for b16):

#line 425 "numpy\\core\\src\\_simd\\_simd.dispatch.c.src"
static PyObject *simd__intrin_and_b16 (PyObject* (__NPY_UNUSED_TAGGEDself) , PyObject *args) {
simd_arg arg1 = {.dtype = simd_data_vb16};
simd_arg arg2 = {.dtype = simd_data_vb16};
if (!PyArg_ParseTuple( args, "O&O&:""and_b16", simd_arg_converter, &arg1, simd_arg_converter, &arg2 ))
return ((void *)0);
simd_data data = {.vb16 = _kand_mask32( arg1.data.vb16, arg2.data.vb16 )};
simd_arg_free(&arg1);
simd_arg_free(&arg2);
simd_arg ret = { .data = data, .dtype = simd_data_vb16 };
return simd_arg_to_obj(&ret);
}

Note the call to _kand_mask32 in the middle. That is defined elsewhere as

extern __mmask32 __cdecl _kand_mask32(__mmask32, __mmask32);

So somehow the macro is setting up the wrong function?

`build.log`

Some of the log lines are very long.

C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.22.27905\bin\HostX86\x64\cl.exe /c /nologo /Ox /W3 /GL /DNDEBUG /MD -DNPY_INTERNAL_BUILD=1 -DHAVE_NPY_CONFIG_H=1 -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE=1 -D_LARGEFILE64_SOURCE=1 -Ibuild\src.win-amd64-3.8\numpy\core\src\_simd -Inumpy\core\include -Ibuild\src.win-amd64-3.8\numpy\core\include/numpy -Ibuild\src.win-amd64-3.8\numpy\distutils\include -Inumpy\core\src\common -Inumpy\core\src -Inumpy\core -Inumpy\core\src\npymath -Inumpy\core\src\multiarray -Inumpy\core\src\umath -Inumpy\core\src\npysort -Inumpy\core\src\_simd -IC:\pypy_stuff\Python38\include -IC:\pypy_stuff\Python38\include -Ibuild\src.win-amd64-3.8\numpy\core\src\common -Ibuild\src.win-amd64-3.8\numpy\core\src\npymath -IC:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.22.27905\ATLMFC\include -IC:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.22.27905\include -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\ucrt -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\shared -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\um -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\winrt -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\cppwinrt -IC:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE -IC:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\ATLMFC\INCLUDE -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\ucrt -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\shared -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\um -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\winrt /Tcbuild\src.win-amd64-3.8\numpy\core\src\_simd\_simd.dispatch.avx512_skx.c /Fobuild\temp.win-amd64-3.8\Release\build\src.win-amd64-3.8\numpy\core\src\_simd\_simd.dispatch.avx512_skx.obj /WX /arch:AVX512
Running from numpy source directory.
C:\pypy_stuff\numpy\numpy\distutils\system_info.py:1989: UserWarning:
Optimized (vendor) Blas libraries are not found.
Falls back to netlib Blas library which has worse performance.
A better performance should be easily gained by switching
Blas library.
if self._calc_info(blas):
C:\pypy_stuff\numpy\numpy\distutils\system_info.py:1989: UserWarning:
Blas (http://www.netlib.org/blas/) libraries not found.
Directories to search for the libraries can be specified in the
numpy/distutils/site.cfg file (section [blas]) or by setting
the BLAS environment variable.
if self._calc_info(blas):
C:\pypy_stuff\numpy\numpy\distutils\system_info.py:1989: UserWarning:
Blas (http://www.netlib.org/blas/) sources not found.
Directories to search for the sources can be specified in the
numpy/distutils/site.cfg file (section [blas_src]) or by setting
the BLAS_SRC environment variable.
if self._calc_info(blas):
C:\pypy_stuff\numpy\numpy\distutils\system_info.py:1849: UserWarning:
Lapack (http://www.netlib.org/lapack/) libraries not found.
Directories to search for the libraries can be specified in the
numpy/distutils/site.cfg file (section [lapack]) or by setting
the LAPACK environment variable.
return getattr(self, '_calc_info_{}'.format(name))()
C:\pypy_stuff\numpy\numpy\distutils\system_info.py:1849: UserWarning:
Lapack (http://www.netlib.org/lapack/) sources not found.
Directories to search for the sources can be specified in the
numpy/distutils/site.cfg file (section [lapack_src]) or by setting
the LAPACK_SRC environment variable.
return getattr(self, '_calc_info_{}'.format(name))()
Warning: attempted relative import with no known parent package
C:\pypy_stuff\Python38\lib\distutils\dist.py:274: UserWarning: Unknown distribution option: 'define_macros'
warnings.warn(msg)
_simd.dispatch.avx512_skx.c
numpy\core\src\_simd\_simd.dispatch.c.src(425): error C2220: warning treated as error - no 'object' file generated
numpy\core\src\_simd\_simd.dispatch.c.src(425): warning C4244: 'initializing': conversion from '__mmask16' to 'npyv_b64', possible loss of data
numpy\core\src\_simd\_simd.dispatch.c.src(426): warning C4244: 'initializing': conversion from '__mmask16' to 'npyv_b64', possible loss of data
numpy\core\src\_simd\_simd.dispatch.c.src(427): warning C4244: 'initializing': conversion from '__mmask16' to 'npyv_b64', possible loss of data
numpy\core\src\_simd\_simd.dispatch.c.src(428): warning C4244: 'initializing': conversion from '__mmask16' to 'npyv_b64', possible loss of data

########### EXT COMPILER OPTIMIZATION ###########
Platform :
Architecture: x64
Compiler : msvc

CPU baseline :
Requested : 'min'
Enabled : SSE SSE2 SSE3
Flags : none
Extra checks: none

CPU dispatch :
Requested : 'max -xop -fma4'
Enabled : SSSE3 SSE41 POPCNT SSE42 AVX F16C FMA3 AVX2 AVX512F AVX512CD AVX512_SKX AVX512_CLX AVX512_CNL AVX512_ICL
Generated :
:
SSE41 : SSE SSE2 SSE3 SSSE3
Flags :
Extra checks: none
Detect : SSE SSE2 SSE3 SSSE3 SSE41
: numpy\core\src\umath\_umath_tests.dispatch.c
:
SSE42 : SSE SSE2 SSE3 SSSE3 SSE41 POPCNT
Flags :
Extra checks: none
Detect : SSE SSE2 SSE3 SSSE3 SSE41 POPCNT SSE42
: build\src.win-amd64-3.8\numpy\core\src\_simd\_simd.dispatch.c
:
AVX2 : SSE SSE2 SSE3 SSSE3 SSE41 POPCNT SSE42 AVX F16C FMA3
Flags : /arch:AVX2
Extra checks: none
Detect : AVX F16C FMA3 AVX2
: build\src.win-amd64-3.8\numpy\core\src\umath\loops_arithm_fp.dispatch.c
: build\src.win-amd64-3.8\numpy\core\src\umath\loops_trigonometric.dispatch.c
: numpy\core\src\umath\_umath_tests.dispatch.c
: build\src.win-amd64-3.8\numpy\core\src\_simd\_simd.dispatch.c
:
AVX512F : SSE SSE2 SSE3 SSSE3 SSE41 POPCNT SSE42 AVX F16C FMA3 AVX2 AVX512CD AVX512_SKX
Flags : /arch:AVX512
Extra checks: none
Detect : AVX512_SKX
: build\src.win-amd64-3.8\numpy\core\src\umath\loops_arithm_fp.dispatch.c
: build\src.win-amd64-3.8\numpy\core\src\umath\loops_trigonometric.dispatch.c
:
AVX512_SKX : SSE SSE2 SSE3 SSSE3 SSE41 POPCNT SSE42 AVX F16C FMA3 AVX2 AVX512F AVX512CD
Flags : /arch:AVX512
Extra checks: AVX512BW_MASK
Detect : AVX512_SKX
: build\src.win-amd64-3.8\numpy\core\src\_simd\_simd.dispatch.c
CCompilerOpt._cache_write[796] : write cache to path -> C:\pypy_stuff\numpy\build\temp.win-amd64-3.8\Release\ccompiler_opt_cache_ext.py

########### CLIB COMPILER OPTIMIZATION ###########
Platform :
Architecture: x64
Compiler : msvc

CPU baseline :
Requested : 'min'
Enabled : SSE SSE2 SSE3
Flags : none
Extra checks: none

CPU dispatch :
Requested : 'max -xop -fma4'
Enabled : SSSE3 SSE41 POPCNT SSE42 AVX F16C FMA3 AVX2 AVX512F AVX512CD AVX512_SKX AVX512_CLX AVX512_CNL AVX512_ICL
Generated : none
CCompilerOpt._cache_write[796] : write cache to path -> C:\pypy_stuff\numpy\build\temp.win-amd64-3.8\ccompiler_opt_cache_clib.py
error: Command "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.22.27905\bin\HostX86\x64\cl.exe /c /nologo /Ox /W3 /GL /DNDEBUG /MD -DNPY_INTERNAL_BUILD=1 -DHAVE_NPY_CONFIG_H=1 -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE=1 -D_LARGEFILE64_SOURCE=1 -Ibuild\src.win-amd64-3.8\numpy\core\src\_simd -Inumpy\core\include -Ibuild\src.win-amd64-3.8\numpy\core\include/numpy -Ibuild\src.win-amd64-3.8\numpy\distutils\include -Inumpy\core\src\common -Inumpy\core\src -Inumpy\core -Inumpy\core\src\npymath -Inumpy\core\src\multiarray -Inumpy\core\src\umath -Inumpy\core\src\npysort -Inumpy\core\src\_simd -IC:\pypy_stuff\Python38\include -IC:\pypy_stuff\Python38\include -Ibuild\src.win-amd64-3.8\numpy\core\src\common -Ibuild\src.win-amd64-3.8\numpy\core\src\npymath -IC:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.22.27905\ATLMFC\include -IC:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.22.27905\include -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\ucrt -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\shared -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\um -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\winrt -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\cppwinrt -IC:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE -IC:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\ATLMFC\INCLUDE -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\ucrt -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\shared -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\um -IC:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\winrt /Tcbuild\src.win-amd64-3.8\numpy\core\src\_simd\_simd.dispatch.avx512_skx.c /Fobuild\temp.win-amd64-3.8\Release\build\src.win-amd64-3.8\numpy\core\src\_simd\_simd.dispatch.avx512_skx.obj /WX /arch:AVX512" failed with exit status 2

Issue 2:
This would probably help with SEO pointing to the new docs site.

As it is, a lot of links are now pointing at stale 1.17 docs, without the reader really being aware that they're looking in the wrong place.

I'm not sure exactly how docs.scipy.org is hosted, but one option might just be to add something like this to a .htaccess:

Redirect 301 /doc/numpy/ https://numpy.org/doc/1.17/