better bigtiff detection

update Changelog and bump version

ChangeLog

@@ -1,3 +1,6 @@
+27/10/14 started 7.40.12
+- better tiff detection (Lovell)
+
 8/10/14 started 7.40.11
 - rework extra band handling for colour functions
 - set interpretation of matlut output more carefully

configure.ac

@@ -2,7 +2,7 @@
 
 # also update the version number in the m4 macros below
 
-AC_INIT([vips], [7.40.11], [vipsip@jiscmail.ac.uk])
+AC_INIT([vips], [7.40.12], [vipsip@jiscmail.ac.uk])
 # required for gobject-introspection
 AC_PREREQ(2.62)
 
@@ -18,7 +18,7 @@ AC_CONFIG_MACRO_DIR([m4])
 # user-visible library versioning
 m4_define([vips_major_version], [7])
 m4_define([vips_minor_version], [40])
-m4_define([vips_micro_version], [11])
+m4_define([vips_micro_version], [12])
 m4_define([vips_version],
           [vips_major_version.vips_minor_version.vips_micro_version])
 
@@ -38,7 +38,7 @@ VIPS_VERSION_STRING=$VIPS_VERSION-`date`
 #   binary interface changes not backwards compatible?: reset age to 0
 
 LIBRARY_CURRENT=38
-LIBRARY_REVISION=7
+LIBRARY_REVISION=8
 LIBRARY_AGE=0
 
 # patched into include/vips/version.h

libvips/foreign/tiff2vips.c

@@ -148,6 +148,8 @@
  * 	- add read from buffer
  * 30/4/14
  * 	- 1/2/4 bit palette images can have alpha
+ * 27/10/14 Lovell
+ * 	- better istiff detector spots bigtiff
  */
 
 /*