Ninja + cmake on Windows build error

[cartesius82]

Cannot build ZSTD using ninja + cmake (versions below) on Windows. Perhaps it's the cmake's fault but is there any workaround? msbuild generator works fine.

cmake ..\build\cmake\ -G Ninja

...
-- Performing Test C_FLAG_WCAST_ALIGN
-- Performing Test C_FLAG_WCAST_ALIGN - Success
-- Performing Test CXX_FLAG_WCAST_ALIGN
-- Performing Test CXX_FLAG_WCAST_ALIGN - Success
-- Performing Test C_FLAG_WCAST_QUAL
-- Performing Test C_FLAG_WCAST_QUAL - Success
-- Performing Test CXX_FLAG_WCAST_QUAL
-- Performing Test CXX_FLAG_WCAST_QUAL - Success
-- Performing Test C_FLAG_WSTRICT_PROTOTYPES
-- Performing Test C_FLAG_WSTRICT_PROTOTYPES - Success
-- Performing Test C_FLAG_DDEBUGLEVEL_1
-- Performing Test C_FLAG_DDEBUGLEVEL_1 - Success
-- Performing Test CXX_FLAG_DDEBUGLEVEL_1
-- Performing Test CXX_FLAG_DDEBUGLEVEL_1 - Success
-- CMAKE_INSTALL_PREFIX: C:/Program Files (x86)/zstd
-- CMAKE_INSTALL_LIBDIR: lib
-- ZSTD_LEGACY_SUPPORT not defined!
-- ZSTD_MULTITHREAD_SUPPORT is enabled
-- Configuring done
-- Generating done
CMake Error:
  Running

   'C:/Users/james/scoop/shims/ninja.exe' '-C' 'C:/Users/james/src/xxx/third_party/zstd/b' '-t' 'recompact'

  failed with:

   ninja: error: build.ninja:767: multiple rules generate lib/zstd.lib [-w dupbuild=err]

Trying -w dupbuild=warn leads to errors as well.

Versions

• cmake version 3.21.2
• ninja 1.10.2
• commit a488ba1 (HEAD, tag: v1.5.0, origin/release)

[cartesius82]

@Cyan4973 Thank you for proper tagging. Any help would be appreciated.

[jannkoeker]

You are propably using Clang (not Clang-cl)
See #2248 (comment)

[terrelln]

Is there any action for us to take on this issue?

[jannkoeker]

The best way would be to extend this code block

zstd/build/cmake/lib/CMakeLists.txt

Lines 108 to 113 in c2c6a4a

	# With MSVC static library needs to be renamed to avoid conflict with import library
	if (MSVC)
	set(STATIC_LIBRARY_BASE_NAME zstd_static)
	else ()
	set(STATIC_LIBRARY_BASE_NAME zstd)
	endif ()

to add an additional check for Clang on Windows.
I will create a pull request as soon as I have time.