[niepce] more warning: overloaded-virtual

[Hubert Figuière <hub src gnome org>]

commit aa975488d82c9881b15b87079e4d60fccd28a425
Author: Hubert Figuière <hub figuiere net>
Date:   Sun Sep 25 17:10:45 2016 -0400

    more warning: overloaded-virtual

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 1574336..0762c71 100644
--- a/configure.ac
+++ b/configure.ac
@@ -131,7 +131,7 @@ AX_APPEND_COMPILE_FLAGS([ \
    -Wlogical-not-parentheses \
    -Wmisleading-indentation \
    -Wmissing-noreturn \
-dnl   -Wno-overloaded-virtual \
+   -Woverloaded-virtual \
    -Wpointer-arith \
 dnl   -Wredundant-decls \
    -Wpointer-bool-conversion \