CMake Warning:
  Manually-specified variables were not used by the project:

    ALSOFT_TESTS
    CMAKE_EXPORT_NO_PACKAGE_REGISTRY


/Applications/Xcode-9.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: ../lib/libopenal.a(alfstream.cpp.o) has no symbols
/Applications/Xcode-9.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: ../lib/libopenal.a(uiddefs.cpp.o) has no symbols
/Applications/Xcode-9.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: ../lib/libopenal.a(mixer_sse3.cpp.o) has no symbols
/Applications/Xcode-9.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: ../lib/libopenal.a(alfstream.cpp.o) has no symbols
/Applications/Xcode-9.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: ../lib/libopenal.a(uiddefs.cpp.o) has no symbols
/Applications/Xcode-9.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: ../lib/libopenal.a(mixer_sse3.cpp.o) has no symbols
/Applications/Xcode-9.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: /Users/jenkins/w/cci_PR-3658@2/.conan/data/openal/1.21.0/_/_/package/af96383df8ed9748d2eed48fb04099c5914a718f/lib/libopenal.a(alfstream.cpp.o) has no symbols
/Applications/Xcode-9.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: /Users/jenkins/w/cci_PR-3658@2/.conan/data/openal/1.21.0/_/_/package/af96383df8ed9748d2eed48fb04099c5914a718f/lib/libopenal.a(uiddefs.cpp.o) has no symbols
/Applications/Xcode-9.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: /Users/jenkins/w/cci_PR-3658@2/.conan/data/openal/1.21.0/_/_/package/af96383df8ed9748d2eed48fb04099c5914a718f/lib/libopenal.a(mixer_sse3.cpp.o) has no symbols
CMake Warning:
  Manually-specified variables were not used by the project:

    CMAKE_EXPORT_NO_PACKAGE_REGISTRY


openal/1.21.0: WARN: openal requires a compiler supporting c++14. I don't know whether your compiler does, so I assume it does.