Version 1.0.4 of libesmtp was recently released.
Created attachment 75036 [details] Ebuild for libesmtp-1.0.4
Created attachment 77095 [details, diff] patch against 1.0.3 for 1.0.4 please bump, as it includes an OSX compilation patch. In my attachment, I included the patch against the 1.0.3 ebuild I made. I removed the gnu_config stuff, as I didn't really needed it, not sure whatfor it was actually.
Bumped in CVS. Thanks for reporting and sorry it took a while!