wopconst was wrong

struct offset astray meant that wopconst didn't work

ChangeLog

@@ -1,3 +1,9 @@
+16/7/12 started 7.28.10
+- wopconst was broken
+- vips_sign() was broken
+- png save compression range was wrong
+- more/moreeq was wrong
+
 18/6/12 started 7.28.9
 - slightly more memory debugging output
 - remove references to the static bicubic interpolator from the docs

configure.in

@@ -2,7 +2,7 @@
 
 # also update the version number in the m4 macros below
 
-AC_INIT(vips, 7.28.9, vipsip@jiscmail.ac.uk)
+AC_INIT(vips, 7.28.10, vipsip@jiscmail.ac.uk)
 # required for gobject-introspection
 AC_PREREQ(2.62)
 
@@ -15,7 +15,7 @@ AC_CONFIG_MACRO_DIR([m4])
 # user-visible library versioning
 m4_define([vips_major_version], [7])
 m4_define([vips_minor_version], [28])
-m4_define([vips_micro_version], [9])
+m4_define([vips_micro_version], [10])
 m4_define([vips_version],
           [vips_major_version.vips_minor_version.vips_micro_version])
 
@@ -35,7 +35,7 @@ VIPS_VERSION_STRING=$VIPS_VERSION-`date`
 #   interface changes not backwards compatible?: reset age to 0
 
 LIBRARY_CURRENT=33
-LIBRARY_REVISION=1
+LIBRARY_REVISION=2
 LIBRARY_AGE=1
 
 # patched into include/vips/version.h

libvips/arithmetic/math2.c

@@ -22,6 +22,8 @@
  * 	- im_powtra() adapated to make math2.c
  * 12/11/11
  * 	- redone as a class
+ * 17/7/12
+ * 	- wopconst was broken
  */
 
 /*
@@ -401,7 +403,7 @@ vips_math2_const_class_init( VipsMath2ConstClass *class )
 		_( "Operation" ), 
 		_( "math to perform" ),
 		VIPS_ARGUMENT_REQUIRED_INPUT,
-		G_STRUCT_OFFSET( VipsMath2, math2 ),
+		G_STRUCT_OFFSET( VipsMath2Const, math2 ),
 		VIPS_TYPE_OPERATION_MATH2, VIPS_OPERATION_MATH2_POW ); 
 }