Mark WINAPI as __stdcall #20

Job	Run time
ubuntu-22.04, default debug	20s
windows-2022, default debug	1m 31s
macos-latest, default debug	27s
windows-2022, gcc debug	1m 34s
ubuntu-22.04, clang debug	22s
ubuntu-22.04, sanitize debug	36s
windows-2022, sanitize+asanonly debug	1m 50s
ubuntu-22.04, clang+sanitize debug	51s
ubuntu-22.04, clang+msan debug	1m 57s
windows-2022, clang-cl+sanitize debug	2m 5s
windows-2022, clang-cl+msan debug	1m 55s
ubuntu-22.04, default release	20s
windows-2022, default release	1m 7s
macos-latest, default release	26s
windows-2022, gcc release	1m 43s
ubuntu-22.04, clang release	23s
ubuntu-22.04, sanitize release	36s
windows-2022, sanitize+asanonly release	1m 33s
ubuntu-22.04, clang+sanitize release	40s
ubuntu-22.04, clang+msan release	30s
windows-2022, clang-cl+sanitize release	1m 49s
windows-2022, clang-cl+msan release	1m 58s
	24m 33s

Provide feedback