cache minimum-?-extent symbols in align-interface.c

diff --git a/lily/align-interface.cc b/lily/align-interface.cc
index efb7986a217ac0bcce84ccf071909af5157990ca..7294335bd9845d961cc1457b3880f936e8632f79 100644 (file)
--- a/lily/align-interface.cc
+++ b/lily/align-interface.cc
@@ -129,7 +129,9 @@ get_skylines (Grob *me,
          /* this is perhaps an abuse of minimum-?-extent: maybe we should create
             another property? But it seems that the only (current) use of
             minimum-Y-extent is to separate vertically-aligned elements */
-         SCM min_extent = g->get_property (a == X_AXIS ? "minimum-X-extent" : "minimum-Y-extent");
+         SCM min_extent = g->get_property (a == X_AXIS
+                                           ? ly_symbol2scm ("minimum-X-extent")
+                                           : ly_symbol2scm ("minimum-Y-extent"));
 
          if (is_number_pair (min_extent))
            {