windows: set CMAKE_MSVC_RUNTIME_LIBRARY for zlib

Since v1.3, zlib advertises compatibility with CMake 3.15 which
added the MSVC_RUNTIME_LIBRARY [1] property, defaulting to the
dynamically-linked runtime library. This seems to overrides our
selection of MSVC runtime library passed through CMAKE_C_FLAGS_<CONFIG>.
Ultimately, this results in a linker error when trying to link libfido2
and zlib.

The generator expression used is the same as the default generator
expression in CMake, with the exception of using the statically linked
runtime library for static builds of libfido2.

[1] https://cmake.org/cmake/help/latest/prop_tgt/MSVC_RUNTIME_LIBRARY.html

windows/build.ps1

@@ -183,6 +183,7 @@ try {
 	    -DBUILD_SHARED_LIBS="${SHARED}" `
 	    -DCMAKE_C_FLAGS_DEBUG="${CFLAGS_DEBUG}" `
 	    -DCMAKE_C_FLAGS_RELEASE="${CFLAGS_RELEASE}" `
+	    -DCMAKE_MSVC_RUNTIME_LIBRARY="${CMAKE_MSVC_RUNTIME_LIBRARY}" `
 	    -DCMAKE_INSTALL_PREFIX="${PREFIX}" "${CMAKE_SYSTEM_VERSION}"; `
 	    ExitOnError
 	& $CMake --build . --config ${Config} --verbose; ExitOnError

windows/const.ps1

@@ -34,9 +34,13 @@ New-Variable -Name 'PREFIX' -Value "${OUTPUT}\${Arch}\${Type}" -Option Constant
 if ("${Type}" -eq "dynamic") {
 	New-Variable -Name 'RUNTIME' -Value '/MD' -Option Constant
 	New-Variable -Name 'SHARED' -Value 'ON' -Option Constant
+	New-Variable -Name 'CMAKE_MSVC_RUNTIME_LIBRARY' -Option Constant `
+	    -Value 'MultiThreaded$<$<CONFIG:Debug>:Debug>DLL'
 } else {
 	New-Variable -Name 'RUNTIME' -Value '/MT' -Option Constant
 	New-Variable -Name 'SHARED' -Value 'OFF' -Option Constant
+	New-Variable -Name 'CMAKE_MSVC_RUNTIME_LIBRARY' -Option Constant `
+	    -Value 'MultiThreaded$<$<CONFIG:Debug>:Debug>'
 }
 New-Variable -Name 'CFLAGS_DEBUG' -Value "${RUNTIME}d /Zi /guard:cf /sdl" `
     -Option Constant