What is wrong with leaving in the manual override option? What is crappy about leaving people the option to not install more abstraction layers on things they don't want? If I want enough abstraction layers I may as well just go use windows and autoupdates.
Did you actually read ./configure --help at some point? Is it your vax experience that did not prevent you from blaming pkg-config that is preventing you from exporting LIBCURL_LIBS and LIBCURL_CFLAGS before running ./configure if so you wish? --with-libcurl option was broken and hence removed. If you don't want to use pkg-config, fine, override the flags and there you go. I have just checked it by uninstalling pkg-config and it works fine.