Building the workspace with `--without-pch` fails on MSVC:
source/lib/sysdep/os/win/acpi.cpp(123): error C3861: 'isalpha':
identifier not found
The pre-compiled header normally brings in `<cctype>`, but when PCH
generation is disabled the translation unit must include the header
explicitly.
Add the missing `#include <cctype>` to
`source/lib/sysdep/os/win/acpi.cpp`.
No functional change; the code now compiles cleanly with or without PCH.
trompetin17
df7b2fcd2a