package/libpagekite: new package

package/libpagekite: new package

libpagekite is a C implementation of the backend of the PageKite relay
protocol. It allows external access to embedded devices without public
IP address.

There is a bundled version of libev but we prefer to use the global
libev library.

Although the configure script has a --without-openssl option, it
doesn't actually build without openssl.

Patch 0001-configure.ac-fix-handling-of-with.patch is needed because
we want to explicitly pass --with and --without options, even if they
are the default. The way the AC_ARG_WITH macros were used, --with and
--without both had the effect of enabling the option.

Patch 0002-configure.ac-use-AS_HELP_STRING-for-with-openssl.patch is
not needed for Buildroot, but it is part of the same upstream PR and
would generate a conflict for the next patch.

Patch 0003-configure.ac-use-pkg-config-for-openssl.patch is needed to
pass -lz (needed by openssl) in static compilation.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Reviewed-by: Romain Naour <romain.naour@smile.fr>
[Thomas:
 - As noticed by Romain Naour, fix the prompt of the package in the
   Config.in
 - Add entry to DEVELOPERS file
 - Drop the dependency on BR2_bfin, since this architecture has been
   dropped from Buildroot.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>