Gentoo's Bugzilla –
Attachment 364428 Details for
Bug 493112app-emulation/spice-0.12.4-r1 with sys-devel/automake-1.14 - common/Makefile.am:4: warning: source file '$(srcdir)/generated_client_demarshallers.c' is in a subdirectory, but option 'subdir-objects' is disabled