There are a few changes in glibc-2.10 that might make your software fail to build with it, please refer to my blog post  if you're not sure what the problem is.
And no I don't usually provide emerge --info with these bugs because they are caused by glibc-2.10!
Created attachment 194155 [details]
Created attachment 201906 [details, diff]
a crude patch with const_casts which enabled the compilation with glibc210
Only tested compilation.
+ 04 Sep 2009; Samuli Suominen <email@example.com>
+ xevil-2.02_p2-r1.ebuild, +files/xevil-2.02_p2-glibc-2.10.patch:
+ Fix building with GLIBC 2.10+ wrt #273557 by Arttu Valo.