git: disable python support if python is not installed

develop/git/git.conf

@@ -12,10 +12,12 @@
 # GNU General Public License can be found in the file COPYING.
 # --- SDE-COPYRIGHT-NOTE-END ---
 
-# disable git-gui if there is no tcl/tk support
-if ! pkginstalled tk; then
-	var_append extraconfopt ' ' "--without-tcltk"
-fi
+for x in tk:tcltk python; do
+	if ! pkginstalled ${x%:*}; then
+		echo_warning "disabling ${x#*:} support"
+		var_append extraconfopt ' ' "--without-${x#*:}"
+	fi
+done
 
 var_append makeopt ' ' 'gitweb'