[gimp] configure.ac: also check for gtk-update-icon-cache-3.0

[Michael Natterer <mitch src gnome org>]

commit df0c659f8b4159620883ddbfa7f710bf94e49461
Author: Michael Natterer <mitch gimp org>
Date:   Sun Jun 2 15:57:42 2019 +0200

    configure.ac: also check for gtk-update-icon-cache-3.0
    
    not only gtk-update-icon-cache, the exacutable name seems to depend on
    how GTK is built and packaged.

 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index 0c2674e8b3..72ba2e6678 100644
--- a/configure.ac
+++ b/configure.ac
@@ -817,7 +817,7 @@ PKG_CHECK_MODULES(GTK, gtk+-3.0 >= gtk_required_version,,
                   [add_deps_error([gtk+-3.0 >= gtk_required_version],
                                   [Test for GTK+ failed.])])
 
-AC_PATH_PROG(GTK_UPDATE_ICON_CACHE, gtk-update-icon-cache, no)
+AC_PATH_PROGS(GTK_UPDATE_ICON_CACHE, gtk-update-icon-cache-3.0 gtk-update-icon-cache, no)
 if test "x$GTK_UPDATE_ICON_CACHE" = xno; then
   add_deps_error([gtk-update-icon-cache],
                  [Could not find gtk-update-icon-cache in your PATH.])