Currently, glibc does not define MAP_POPULATE on SPARC or SPARC64 architectures. Because of this, it never ends up in <bits/mman.h>, making apps like dev-libs/elfutils-0.118 fail to compile. Attached shortly will be a patch based on content from upstream for glibc-2.3.5 (latest ~sparc'd glibc) that will fixed this. While no 2.3.6 versions of glibc are currently keyworded for SPARC or SPARC64, this should be able to be applied there as well. If there are no issues with it, please apply this patch soon. Thanks!
Created attachment 80233 [details, diff] glibc patch to define MAP_POPULATE for SPARC (among other values)
added to 2.3.5-r3 and 2.3.6-r3 if you want revbumps, feel free to do so