The following line in libcurl.m4 lacks a terminating quote which causes Autoconf-generated configure scripts using LIBCURL_CHECK_CONFIG to fail
_libcurl_protocols="HTTP FTP FILE TELNET LDAP DICT TFTP
Patch attached.
Curl: 7.20.0 Linux i686
autoconf: 2.65
Patch adding a terminating quote to __libcurl_protocols
Thanks for the report, this problem is now fixed in CVS!