Vladislav Mikhalin added the comment:
The documentation states:
-E Don't fetch or build external libraries. Extension modules that
depend on external libraries will not attempt to build if this flag
is present; -e is also accepted to explicitly enable fetching
New submission from Vladislav Mikhalin :
These errors are generated on a clean build:
C:\cpython-3.8.5\Modules\_ctypes\_ctypes.c(107,10): fatal error C1083: Cannot
open include file: 'ffi.h': No such file or directory
[C:\cpython-3.8.5\PCbuild\_ctypes.vcxproj]
C:\cpython-3.8.5\Modules
