merge revision(s) a0bc3f2a,75a0447c,f1699314: [Backport #16846]

	Suppress C4267 "possible loss of data" warnings

	Suppress C4267 "possible loss of data" warnings

	Just cast down explicitly.

	win32ole: separate global variable declarations and definitions

	https://gcc.gnu.org/gcc-10/changes.html#c

	> * GCC now defaults to `-fno-common`.  As a result, global
	>   variable accesses are more efficient on various targets.  In
	>   C, global variables with multiple tentative definitions now
	>   result in linker errors.  With `-fcommon` such definitions are
	>   silently merged during linking.