The gtk-doc m4 macros are required for the call to eautoreconf, without dev-util/gtk-doc-am the build will fail. Thanks, James Reproducible: Always
Created attachment 202145 [details, diff] libgpepimc-0.9-build_requires_gtk-doc-am.patch
It is fixed on CVS. I'll search for other ebuilds that depend on the GTK_DOC_CHECK M4 macro. Thank you for reporting.