This enables "classic" desktop builds of ICU4C for both ARM (32-bit)
and ARM64 (64-bit) on Windows.
All but the two samples "cal" and "date" in the "allinone" project now
have ARM and ARM64 project configurations, and build for Windows Desktop
ARM/ARM64.
Note: In order to build the ARM/ARM64 data DLL, you need to first build
x64/Release, as the ARM/ARM build uses the x64 bits in order to be able
to cross-compile for ARM/ARM64. This allows for completely building
ARM/ARM64 binaries using only x64 hardware.
The ARM/ARM64 builds require using a newer version of the Windows SDK
than 8.1, so they have a separate WindowsTargetPlatformVersion which
uses Windows 10 SDK version 10.0.16299.0 (aka RS3), which is the first
version of the Windows SDK to support building ARM64 desktop applications.
In addition this also greatly cleans-up the ICU4C ".vcxproj" files, in
order to remove redundant parts, fix inconsistencies, and make them more
readable. This introduces two new variables in the shared `*.props`
files: `IcuBinOutputDir` and `IcuLibOutputDir` in order to further
reduce the amount of duplicated lines in the individual ".vcxproj"
files themselves.
This also changes the pkgdata tool command line options to decouple the
ARM/ARM64 flags from the UWP flag, and adds a generic architecture
option (-a) for passing in the value of the linker "/MACHINE:" argument
on the command line. (Ex: -a ARM64).
Additionally this change also adds another option to pkgdata (-b) to
set /DYNAMICBASE on the data DLL, which is required for the ARM64 builds.
Both of these changes also work towards future work in order to enable
full ARM64 desktop builds without UWP.
This change also removes a number of ifdefs/forks in the ICU code based
on U_PLATFORM_HAS_WINUWP_API, and changes them to use ICU_DATA_DIR_WINDOWS
instead. This is needed to unblock the usage of the data DLL in the
UWP scenario, but also helps to further reduce the divergence of the UWP
projects from regular Windows builds.
Related tickets:
ICU4C: Remove fixed DLL base addresses when building Windows DLLs
https://unicode-org.atlassian.net/browse/ICU-20768
Add support to generate ICU data DLL for Windows arm64
https://unicode-org.atlassian.net/browse/ICU-20670
In an effort to reduce the number of warnings that building ICU emits, we should set the following define for ICU4C library code when building using MSVC/VisualStudio: _HAS_EXCEPTIONS=0
This tells the MSVC implementation of the STL that exceptions should not be used - which is fine for ICU4C library code, as the library code does not make use of exceptions at all.
