Gentoo's Bugzilla –
Attachment 866820 Details for
Bug 894508app-emulation/gallium-nine-standalone-0.8-r1 fails to compile (MUSL-CLANG-SYSTEM): present.c:1771:24: error: call to undeclared function XrmUniqueQuark; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]