Clean-up: Fix BLI_rect.h collision with windows.h

windows.h `#defines rct1` as a number which is
problematic if we include `BLI_rect.h` after
`windows.h` .

by renaming `rct1/2` to `rct_a/b` we side step
the collision and straighten up the naming with
the functions directly above it.

tests/benchmarks: Fix operation on windows

The test script did not work on windows
since it had some trouble importing the
api module on the blender side of things.

turning the file path to the module into
a raw string literal sidesteps the
backslash issue in the path.

Differential Revision: https://developer.blender.org/D13163

Reviewed by: brecht

Fix: Build error on windows.

External symbols in C files need
to be marked as such otherwise
the linker will not find them.

Fix: Build error on all platforms

Types were used before being declared.

win/make.bat: Add svnfix convenience target

SVN seems to die randomly *a lot* during
large updates for some users, and I'm no
closer to finding out why that keeps happening.

"The internet" seems to imply some AV vendors
may be at fault here but nothing conclusive.

The solution however is repeatedly running
`svn cleanup`and `svn update` in the library
folder to repair the corruption and finish the
update.

This change adds a small convenience helper
to automate the repair.

This is done inside the make.bat code rather
than the shared python based update code, since
python lives in the library folder and may
or may not exist when this corruption occurs.

Revert "Eevee: support accessing custom mesh attributes"

This reverts commit 03013d19d16704672f9db93bc62547651b6a5cb8.

This commit broke the windows build pretty badly and I don't
feel confident landing the fix for this without review.

Will post a possible fix in D12969 and we'll take it from there.

Fix: Build issue on windows

Empty initializer is not appreciated by MSVC.

Windows: Fix finding python for build helpers

It was still looking for the 3.7 folder
rather than 3.9

Fix: Build error with MSVC

noise.cc uses std::min and std::max without
including the algorithm header required.

Newer MSVC versions and GCC implicitly include
it somewhere, which isn't something we should
count on. Best to include what you use.

Fix: T91602 ffmpeg crash

Issue caused by our patch in rB1af722b81912
we replaced an array with a memory allocation
but we forgot to update the assert which now
used an invalid method to calculate the array
size.

SVN libs will have to be updated before
T91602 will be fixed for end users.