cmake fails to compile on Leopard (lround)

[rmottola (Riccardo)]

Build log attached, it fails with clang 3.9 clang 5.0 and gcc 6.5 (even my patched gcc6 which has fixed math headers).

Lots of warnings, but the issues seems to be:

opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_cmake/cmake/work/cmake-3.14.5/Source/cmFileCommand.cxx:2615:66: error: call of overloaded 'lround(double)' is ambiguous
       this->CurrentPercentage = std::lround(value / total * 100.0);
                                                                  ^
In file included from /opt/local/include/LegacySupport/cmath:54:0,
                 from /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_cmake/cmake/work/cmake-3.14.5/Source/cmFileCommand.cxx:13:
/opt/local/include/gcc6/c++/cmath:1662:3: note: candidate: constexpr long int std::lround(float)
   lround(float __x)
   ^~~~~~
/opt/local/include/gcc6/c++/cmath:1666:3: note: candidate: constexpr long int std::lround(long double)
   lround(long double __x)
   ^~~~~~
make[2]: *** [Source/CMakeFiles/CMakeLib.dir/cmFileCommand.cxx.o] Error 1

An issue with legacy support?

[cjones051073 (Chris Jones)]

This doesn't look like an issue with LegacySupport to me. Its only mentioned above because /opt/local/include/LegacySupport/cmath happens to wrap the 'system' cmath file. Also note the legacy support header does nothing to the 'lround' methods, it only adds the 'll' versions.