Created attachment 306255 [details, diff]
Patch to vixie-cron-4.1-r12.ebuild to move sed as described below
In sys-process/vixie-cron-4.1-r12, the latest ebuild available as of this writing, src_compile() uses sed -i to resolve some QA issues in the upstream Makefile. However, the ebuild expands $CFLAGS and $LDFLAGS on the spot and includes them in the sed command line, rather than directing sed to place "$(CFLAGS)" and "$(LDFLAGS)" in the Makefile, where make will expand them when the rules are evaluated. This is suboptimal, since certain unusual values of CFLAGS can confuse sed, but would work correctly if passed in the environment to be expanded by make. In my case, an attempt to pass through a value with an embedded colon tripped up the sed substitution.
The attached patch moves the sed from src_compile to src_unpack (to be with the other source patching directives), deletes the assignments of CFLAGS and LDFLAGS (allowing make to inherit the proper values from the environment), renames INCLUDE to CPPFLAGS so that it will be automatically used, and adjusts the linking rules to include $CFLAGS and $CPPFLAGS. I believe that, for typical environments, this patch is a no-op, so no revbump is needed.