package/libkrb5: add openssl optional dependency

openssl is an optional dependency which is enabled by default since at
least 2007 and
https://github.com/krb5/krb5/commit/4c17f25c0f106ec8e3aad2cee4e7a24f66b5a65d

Enable DES, MD4 and RC4 in openssl to fix build failure raised since
commit a83d41867c8d69a77d5cd0a665aa216af5340359

Fixes:
 - http://autobuild.buildroot.org/results/d73b477bd2064aee076f9debfd8d3346c63ba657

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[yann.morin.1998@free.fr: squash the two commits together]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit b7a5b9d06d484700fc4fcbd354f2c15e0422688c)
[Peter: drop openssl options]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libkrb5/libkrb5.mk

@@ -41,6 +41,21 @@ else
 LIBKRB5_CONF_OPTS += --without-ldap
 endif
 
+ifeq ($(BR2_PACKAGE_OPENSSL),y)
+LIBKRB5_CONF_OPTS += \
+	--enable-pkinit \
+	--with-crypto-impl=openssl \
+	--with-spake-openssl \
+	--with-tls-impl=openssl
+LIBKRB5_DEPENDENCIES += openssl
+else
+LIBKRB5_CONF_OPTS += \
+	--disable-pkinit \
+	--with-crypto-impl=builtin \
+	--without-spake-openssl \
+	--without-tls-impl
+endif
+
 ifeq ($(BR2_PACKAGE_LIBEDIT),y)
 LIBKRB5_CONF_OPTS += --with-libedit
 LIBKRB5_DEPENDENCIES += host-pkgconf libedit