Currenlty libmicrohttpd use-deps on net-misc/curl[ssl,-nss] and other combinations of the use flags. But as of curl-7.25.0-r1, backend ssl providers are chosen via CURL_SSL use expand flag, so, moving forward, these dependency should change nss -> curl_ssl_nss, etc. when depending on >=curl-7.25.0-r1. See bug #412431 for more details. Reproducible: Always
Created attachment 309441 [details, diff] add CURL_SSL use expand to libmicrohttpd-0.9.19.ebuild Added a small patch that addresses this issue.
The suggestions from comment 0 and 1 seem a bit complex to me. EAPI=4 USE conditionals would allow a more elegant solution - >=net-misc/curl-7.21[ssl,-nss] >=net-misc/curl-7.21[ssl,gnutls] + >=net-misc/curl-7.21[ssl,-nss(-),-curl_ssl_nss(-)] >=net-misc/curl-7.21[ssl,gnutls]
Fixed in 0.9.20