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. Also make sure to fix it rather than sidestepping the issue  and .
And no I don't usually provide emerge --info with these bugs because they are caused by glibc-2.10!
Created attachment 198311 [details]
Ok, while looking at this one, I found two things:
* this "Assumed value of MB_LEN_MAX wrong" from stdlib.h is strange, and this may be a problem in gnustep base itself (from the long include path). Moreover it disappears with empty CFLAGS (probably -O2)...
* second, I've realized that as for now, changing CFLAGS/LDFLAGS/... requires gnustep-make re-merging to take into account :/ (it loads CFLAGS and other vars from /usr/GNUstep/System/Library/Makefiles/config.make, not from environment). If this is confirmed for other packages, an ewarn in gnustep-make could be useful, before ideally managing to override it. Adding to todo list...
Ok, found it: limits.h is sometimes included by #import instead of #include, and with optimization it somehow believes it's already included, and does not load it, which leads to the error in stdlib.h
Fixed in 0.8.3 (version bump at the same time)!