add libmicrohttpd component

component/libmicrohttpd/buildout.cfg

+[buildout]
+extends =
+  ../libiconv/buildout.cfg
+  ../gnutls/buildout.cfg
+  ../curl/buildout.cfg
+
+parts =
+  libmicrohttpd
+
+
+[libmicrohttpd]
+recipe = slapos.recipe.cmmi
+url = https://ftp.gnu.org/gnu/libmicrohttpd/libmicrohttpd-0.9.70.tar.gz
+md5sum = dcd6045ecb4ea18c120afedccbd1da74
+configure-options =
+  --with-libcurl=${curl:location}
+  --with-gnutls=${gnutls:location}
+  --with-libiconv-prefix=${libiconv:location}
+  --without-libintl-prefix