Bug#783838: blender: FTBFS in Jessie

[Edmund Grimley Evans]

Source: blender
Version: 2.72.b+dfsg0-3

It failed to build in Jessie, amd64 and arm64. In each case the error
was:

/«BUILDDIR»/blender-2.72.b+dfsg0/source/blender/blenfont/intern/blf_glyph.c: In
function 'blf_glyph_add':
/«BUILDDIR»/blender-2.72.b+dfsg0/source/blender/blenfont/intern/blf_glyph.c:265:13:
error: conversion to 'int' from 'unsigned int' may change the sign of
the result [-Werror=sign-conversion]
  g->width = bitmap.width;
             ^
/«BUILDDIR»/blender-2.72.b+dfsg0/source/blender/blenfont/intern/blf_glyph.c:266:14:
error: conversion to 'int' from 'unsigned int' may change the sign of
the result [-Werror=sign-conversion]
  g->height = bitmap.rows;
              ^
cc1: some warnings being treated as errors