"Unsupported argument with another option" build failure(s) — clang 5.0

PackageVersionSupposed error messageFull log Bug report
3dchess 0.8.1-20clang: error: unsupported option '-fpcc-struct-return' for target 'x86_64-pc-linux-gnu' Log
autodock-vina 1.1.2-3clang: error: unsupported option '--lto' Log
crawl 2:0.20.1-1clang: error: unsupported argument 'jobserver' to option 'flto=' Log
freecontact 1.0.21-6clang: error: unsupported option '--help=optimizers' Log
libffi 3.2.1-6clang: error: unsupported option '-print-multi-os-directory' Log
libre 0.5.4-3clang: error: unsupported option '--print-multiarch' Log
qtwebkit 2.3.4.dfsg-9.1clang: error: unsupported option '-gstabs' Log
qtwebkit-opensource-src 5.9.1+dfsg-3clang: error: unsupported option '-gstabs' Log
stalin 0.11-6clang: error: unsupported option '-freg-struct-return' for target 'x86_64-pc-linux-gnu' Log
supermin 5.1.18-1clang: error: unsupported option '-specs /usr/share/dpkg/no-pie-compile.specs' Log
syslinux 3:6.03+dfsg-14.1clang: error: unsupported option '--print-libgcc' Log

11 errors