Note: This uses the generic curlbuild.h because it is used by multiple platforms.
A system curl would have a configure generated one.
The libraries for win32 and win64 were cross compiled with these options:
--disable-shared --enable-static --disable-ares --enable-http \
--enable-ftp --disable-ldap --disable-ldaps --disable-rtsp \
--disable-dict --disable-file --disable-telnet --disable-tftp \
--disable-pop3 --disable-imap --disable-smtp --disable-gopher \
--enable-ipv6 --without-ssl \
--disable-manual --disable-libcurl-option
This effectively enables only HTTP and FTP protocol support.
