Created attachment 388310 [details] build log gcc-4.8.3 rebuilds were triggered by a new 'sanitize' USE flag. However, the ebuild does not compile for 64-bit MinGW targets with that USE flag enabled. Following up after #525942, the build is broken by an explicit #error directive in GCC's libsanitizer. I suggest USE=sanitize be masked for Windows profiles.
Created attachment 388312 [details] emerge --info
*** This bug has been marked as a duplicate of bug 525910 ***