arb_texture_buffer_object: fix buffer size
GL_MAX_TEXTURE_BUFFER_SIZE_ARB + 1 won't necessarly fit in an int32_t so use a int64_t in the computation.
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
GL_MAX_TEXTURE_BUFFER_SIZE_ARB + 1 won't necessarly fit in an int32_t so use a int64_t in the computation.