Add ruby 2.3 detection

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

lib/kross/configure.in.in

@@ -36,28 +36,13 @@ if test "x$compile_kross" = "xyes" ; then
         RUBY_CFLAGS=`$PKGCONFIG ruby --cflags`
       fi
       if test -z "$RUBY_VERSION"; then
-        RUBY_VERSION=`$PKGCONFIG ruby-2.2 --modversion 2>/dev/null`
+        for RUBY_TEST in 2.3 2.2 2.1 2.0 1.9; do
+          RUBY_VERSION=`$PKG_CONFIG ruby-$RUBY_TEST --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 "$RUBY_VERSION"; then
-          RUBY_CFLAGS=`$PKGCONFIG ruby-2.1 --cflags`
-        fi
-      fi
-      if test -z "$RUBY_VERSION"; then
-        RUBY_VERSION=`$PKGCONFIG ruby-2.0 --modversion 2>/dev/null`
-        if test -n "$RUBY_VERSION"; then
-          RUBY_CFLAGS=`$PKGCONFIG ruby-2.0 --cflags`
-        fi
-      fi
-      if test -z "$RUBY_VERSION"; then
-        RUBY_VERSION=`$PKGCONFIG ruby-1.9 --modversion 2>/dev/null`
-        if test -n "$RUBY_VERSION"; then
-          RUBY_CFLAGS=`$PKGCONFIG ruby-1.9 --cflags`
+            RUBY_CFLAGS=`$PKG_CONFIG ruby-$RUBY_TEST --cflags`
+            break
           fi
+        done
       fi
       if test -z "$RUBY_VERSION"; then
         # pkgconfig file does not exist but might be 1.9.1: RUBY_VERSION defined in ruby/version.h