Add ruby 2.2 detection

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>

lib/kross/configure.in.in

@@ -35,6 +35,12 @@ if test "x$compile_kross" = "xyes" ; then
       if test -n "$RUBY_VERSION"; then
         RUBY_CFLAGS=`$PKGCONFIG ruby --cflags`
       fi
+      if test -z "$RUBY_VERSION"; then
+        RUBY_VERSION=`$PKGCONFIG ruby-2.2 --modversion 2>/dev/null`
+        if test -n "$RUBY_VERSION"; then
+          RUBY_CFLAGS=`$PKGCONFIG ruby-2.2 --cflags`
+        fi
+      fi
       if test -z "$RUBY_VERSION"; then
         RUBY_VERSION=`$PKGCONFIG ruby-2.1 --modversion 2>/dev/null`
         if test -n "$RUBY_VERSION"; then