Could not cross-build on Windows to armv8 due guard empty CMAKE_SYSTEM_VERSION when linking synchronization

[uilianries]

Description

Greetings!

When trying to cross-build Sentry Native 0.14.0 on Windows x86_64 to ARM, the CMake setup fails with the following error:

CMake Error at CMakeLists.txt:601 (if):
  if given arguments:

    "NOT" "(" "MSVC" "AND" "CMAKE_GENERATOR_TOOLSET" "MATCHES" "_xp\$" ")" "AND" "(" "MATCHES" "^10" "OR" "MATCHES" "^6\\.[23]" ")"

  Unknown arguments specified

Full build log: https://c3i.jfrog.io/artifactory/cci-build-logs/cci/prod/PR-29690/8/package_build_logs/build_log_sentry-native_0_14_0_0882f3e8423701a51763d0f22b80e6cd_2425a446a5805f86a9ea449170118bf5910b5582.txt

The error comes from CMakeLists.txt#L601:

if(NOT (MSVC AND CMAKE_GENERATOR_TOOLSET MATCHES "_xp$")
	AND (${CMAKE_SYSTEM_VERSION} MATCHES "^10"
		OR ${CMAKE_SYSTEM_VERSION} MATCHES "^6\\.[23]"))
	list(APPEND _SENTRY_PLATFORM_LIBS "synchronization")
endif()

The CMAKE_SYSTEM_VERSION is empty when cross-building, which results in that error. A possible fix is guarding that variable, like:

        # WaitOnAddress/WakeByAddressSingle require Windows 8+
        # (Synchronization.lib). Older targets fall back to sleep-poll.
        if(NOT (MSVC AND CMAKE_GENERATOR_TOOLSET MATCHES "_xp$")
-               AND (${CMAKE_SYSTEM_VERSION} MATCHES "^10"
-                       OR ${CMAKE_SYSTEM_VERSION} MATCHES "^6\\.[23]"))
+               AND ("${CMAKE_SYSTEM_VERSION}" MATCHES "^10"
+                       OR "${CMAKE_SYSTEM_VERSION}" MATCHES "^6\\.[23]"))
                list(APPEND _SENTRY_PLATFORM_LIBS "synchronization")
        endif()
 endif()

However, it will not be enough, as synchronization will not be linked, the build will fail when linking:

CMakeFiles\sentry.dir\src\backends\sentry_backend_crashpad.cpp.obj CMakeFiles\sentry.dir\src\unwinder\sentry_unwinder_dbghelp.c.obj CMakeFiles\sentry.dir\src\screenshot\sentry_screenshot_windows.c.obj CMakeFiles\sentry.dir\Release\sentry.rc.res /out:sentry.dll /implib:sentry.lib /pdb:sentry.pdb /dll /version:0.0 /machine:ARM64 /INCREMENTAL:NO dbghelp.lib shlwapi.lib version.lib winhttp.lib crashpad_build\client\crashpad_client.lib crashpad_build\util\crashpad_util.lib crashpad_build\compat\crashpad_compat.lib crashpad_build\third_party\mpack\crashpad_mpack.lib crashpad_build\third_party\zlib\crashpad_zlib.lib user32.lib version.lib winhttp.lib crashpad_build\third_party\mini_chromium\mini_chromium.lib advapi32.lib kernel32.lib rpcrt4.lib kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib /MANIFEST:EMBED,ID=2" failed (exit code 1120) with the following output:
   Creating library sentry.lib and object sentry.exp

sentry_batcher.c.obj : error LNK2019: unresolved external symbol WaitOnAddress referenced in function batcher_thread_func

sentry_batcher.c.obj : error LNK2019: unresolved external symbol WakeByAddressSingle referenced in function sentry__batcher_enqueue

sentry.dll : fatal error LNK1120: 2 unresolved externals

ninja: build stopped: subcommand failed.

Full build log: https://c3i.jfrog.io/artifactory/cci-build-logs/cci/prod/PR-29690/9/package_build_logs/build_log_sentry-native_0_14_0_6a875c3c2ae62f8d51a8498e55372791_2425a446a5805f86a9ea449170118bf5910b5582.txt

---

Still, this is a regression, because it was possible to build Sentry native 0.12.6 without errors, using the very same environment: https://c3i.jfrog.io/artifactory/cci-build-logs/cci/prod/PR-29540/4/package_build_logs/build_log_sentry-native_0_12_6_8e6f0029470062ca9dc6825291f2835f_2425a446a5805f86a9ea449170118bf5910b5582.success.txt

It may be related to a42aca5 and #880

Regards!

When does the problem happen

• During build
• During run-time
• When capturing a hard crash

Environment

• OS: Windows 10, x86_64
• Compiler: MSVC 19.44.35213.0
• CMake version and config: 3.16, backend=crashpad qt=False shared=True transport=winhttp wer=False with_crashpad=sentry

Steps To Reproduce

Please, read the logs which contains the CMake commands used to configure and build.

[linear-code]

NATIVE-188

[jpnurmi]

The proposed fix looks good. Would you like to open a PR?

[uilianries]

Done, created the PR #1720

Let me know if I need to sign a CLA. Regards!