SSL error building library on Windows in configure step

[hamishwillee]

Clean build in windows command prompt after following these instructions https://mavsdk.mavlink.io/main/en/cpp/guide/build.html#windows to install VS tools and cmake.

OpenSSL also seems to cause problems building on Ubuntu.

Configure step finished with

  No update step for 'openssl'
  No patch step for 'openssl'
  Performing configure step for 'openssl'
  'perl' is not recognized as an internal or external command,
  operable program or batch file.
C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Microsoft\VC\v170\Microsoft.CppCommon.targets(254,5): error MSB8066: Custom build for 'D:\github\mavsdk\MAVSDK\build\default\third_party\openssl\CMakeFiles\4cc26649d8cfd21648a879eb2f147cb5\openssl-mkdir.rule;D:\github\mavsdk\MAVSDK\build\default\third_party\openssl\CMakeFiles\4cc26649d8cfd21648a879eb2f147cb5\openssl-download.rule;D:\github\mavsdk\MAVSDK\build\default\third_party\openssl\CMakeFiles\4cc26649d8cfd21648a879eb2f147cb5\openssl-update.rule;D:\github\mavsdk\MAVSDK\build\default\third_party\openssl\CMakeFiles\4cc26649d8cfd21648a879eb2f147cb5\openssl-patch.rule;D:\github\mavsdk\MAVSDK\build\default\third_party\openssl\CMakeFiles\4cc26649d8cfd21648a879eb2f147cb5\openssl-configure.rule;D:\github\mavsdk\MAVSDK\build\default\third_party\openssl\CMakeFiles\4cc26649d8cfd21648a879eb2f147cb5\openssl-build.rule;D:\github\mavsdk\MAVSDK\build\default\third_party\openssl\CMakeFiles\4cc26649d8cfd21648a879eb2f147cb5\openssl-install.rule;D:\github\mavsdk\MAVSDK\build\default\third_party\openssl\CMakeFiles\b8e56295dec8820efe4bf03ee24ddcb8\openssl-complete.rule;D:\github\mavsdk\MAVSDK\build\default\third_party\openssl\CMakeFiles\642fad925227dfd8d73fced3e3738b0d\openssl.rule;D:\github\mavsdk\MAVSDK\third_party\openssl\CMakeLists.txt' exited with code 9009. [D:\github\mavsdk\MAVSDK\build\default\third_party\openssl\openssl.vcxproj]
CMake Error at third_party/cmake/build_target.cmake:51 (message):
  D:/github/mavsdk/MAVSDK/build/default/third_party/openssl failed to build!
Call Stack (most recent call first):
  third_party/CMakeLists.txt:20 (build_target)


-- Configuring incomplete, errors occurred!

Full build log at https://gist.github.com/hamishwillee/a8e54796c88a2a18c1f0b3d738a291b0

[JonasVautherin]

It fails here:

'perl' is not recognized as an internal or external command, operable program or batch file.

Did it use to build, or is it the first time you try on this computer? I don't think we have changed anything for Windows and OpenSSL, so I wonder if we don't "just" require perl to be installed (as a "dev tool")? Not sure 🤔

One thing we changed, though, is that we now always build OpenSSL (even if BUILD_MAVSDK_SERVER=OFF), so that may be it.

[JonasVautherin]

It seems to me that Windows needs Perl for OpenSSL: https://github.com/openssl/openssl/blob/master/NOTES-PERL.md#perl-on-windows.

I found some unofficial instructions here.