Fixes #558: Now `WINDOWS_EXPORT_ALL_SYMBOLS` just for our targets; an… #541

Job	Run time
build (windows-2019, 12.1.1, Visual Studio 16 2019, powershell, windows, -A x64)	14m 20s
build (windows-2019, 12.0.1, Visual Studio 16 2019, powershell, windows, -A x64)	7m 7s
build (windows-2019, 11.8.0, Visual Studio 16 2019, powershell, windows, -A x64)	14m 28s
build (windows-2019, 11.7.0, Visual Studio 16 2019, powershell, windows, -A x64)	14m 27s
build (windows-2019, 11.6.2, Visual Studio 16 2019, powershell, windows, -A x64)	6m 27s
build (windows-2019, 11.6.1, Visual Studio 16 2019, powershell, windows, -A x64)	5m 45s
build (windows-2019, 11.6.0, Visual Studio 16 2019, powershell, windows, -A x64)	7m 57s
build (windows-2019, 11.5.0, Visual Studio 16 2019, powershell, windows, -A x64)	4m 57s
build (windows-2019, 11.4.0, Visual Studio 16 2019, powershell, windows, -A x64)	7m 40s
build (windows-2019, 11.3.0, Visual Studio 16 2019, powershell, windows, -A x64)	5m 31s
build (windows-2019, 11.2.2, Visual Studio 16 2019, powershell, windows, -A x64)	7m 41s
build (windows-2019, 11.1.1, Visual Studio 16 2019, powershell, windows, -A x64)	8m 54s
build (windows-2019, 11.0.3, Visual Studio 16 2019, powershell, windows, -A x64)	9m 7s
	1h 54m 21s

Provide feedback