[gimp] plug-ins: add a new possible format for TIFF tag warning messages.

[Jehan Pagès <jehanp src gnome org>]

commit 02adc61b0513d3a63c7a237187017beb11aa2a84
Author: Jehan <jehan girinstud io>
Date:   Sat Jul 23 18:35:16 2016 +0200

    plug-ins: add a new possible format for TIFF tag warning messages.
    
    Completing fix from commit 3cb70e6.
    Checking further into libtiff logs, I can see another version of the
    warning message for private tags which was used before libtiff 3.7.
    For sake of completeness, let's check against this version of the
    warning as well.

 plug-ins/file-tiff/file-tiff-io.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/plug-ins/file-tiff/file-tiff-io.c b/plug-ins/file-tiff/file-tiff-io.c
index 11339d3..ebe2d84 100644
--- a/plug-ins/file-tiff/file-tiff-io.c
+++ b/plug-ins/file-tiff/file-tiff-io.c
@@ -122,8 +122,10 @@ tiff_io_warning (const gchar *module,
 {
   gint tag = 0;
 
-  /* Before libtiff 4.0.0alpha. */
-  if (! strcmp (fmt, "%s: unknown field with tag %d (0x%x) encountered"))
+  /* Between libtiff 3.7.0beta2 and 4.0.0alpha. */
+  if (! strcmp (fmt, "%s: unknown field with tag %d (0x%x) encountered") ||
+      /* Before libtiff 3.7.0beta2. */
+      ! strcmp (fmt, "%.1000s: unknown field with tag %d (0x%x) encountered"))
     {
       va_list ap_test;