Replace local header placeholders in appinstaller with direct references to upstream headers. Deleted the gitlink/header stubs (certmgr.h, notice.h, pkgmgr.h, pkgread.h, priformatcli.h) from appinstaller, updated main.cpp and appxinfo.h to include the ../path to those headers, and adjusted appinstaller.vcxproj.filters to point to the new locations. Cleans up redundant local links and ensures the project references the original header files.
Add _ARM_WINAPI_PARTITION_DESKTOP_SDK_AVAILABLE=1 to PreprocessorDefinitions in multiple .vcxproj files so ARM desktop SDK partition is available at project level. Remove per-file #ifdef _M_ARM defines from several headers and source files (Stdafx.h, targetver.h, main.cpp across various modules) to avoid duplication. Also add ShowIncludes=false in pkgread.vcxproj. This centralizes the ARM macro for consistent ARM builds across modules.
Upgrade solution to Visual Studio 17 and add ARM build configurations across projects. Several .vcxproj files were updated to include Debug/Release|ARM property groups, property sheet imports and LinkIncremental settings; platform toolset set for ARM configs where appropriate. A new pugixml_arm project and its sources/filters were added. Also added ExtensibilityGlobals (SolutionGuid) to the .sln.
