Defining Windows version macros in meson.build
WINVER and _WIN32_WINNT macros were defined in each source files which were including <windows.h>. However, because DirectWrite requires new Windows API, some files included <windows.h> without the version macros. This inconsistency sometimes caused troubles.
Define those version macros and WIN32_LEAN_AND_MEAN macro consistently in meson.build, not in source files.
Edited by Fujii Hironori