vips.h: fail to build on Debian Jessie

Debian Jessie has libvips 7.40.6.
Problem is that before 7.41, VIPS_ANGLE_DXX did not exists.
So we need to define properly the macro in order to build
for libvips < 7.41

vips.h

@@ -64,6 +64,18 @@ vips_shrink_bridge(VipsImage *in, VipsImage **out, double xshrink, double yshrin
 int
 vips_rotate(VipsImage *in, VipsImage **out, int angle)
 {
+#if (VIPS_MAJOR_VERSION == 7 && VIPS_MINOR_VERSION < 41)
+/*
+ * Starting libvips 7.41, VIPS_ANGLE_x has been renamed to VIPS_ANGLE_Dx
+ * "to help python". So we provide the macro to correctly build for versions
+ * before 7.41.x.
+ * https://github.com/jcupitt/libvips/blob/master/ChangeLog#L128
+ */
+# define VIPS_ANGLE_D0 VIPS_ANGLE_0
+# define VIPS_ANGLE_D90 VIPS_ANGLE_90
+# define VIPS_ANGLE_D180 VIPS_ANGLE_180
+# define VIPS_ANGLE_D270 VIPS_ANGLE_270
+#endif
 	int rotate = VIPS_ANGLE_D0;
 
 	if (angle == 90) {