libgd/gdcache.c libgd/gdkanji.c libgd/wbmp.c libgd/gd_wbmp.c libgd/gdhelpers.c \
libgd/gd_topal.c libgd/gd_gif_in.c libgd/xbm.c libgd/gd_gif_out.c libgd/gd_security.c \
libgd/gd_filter.c libgd/gd_pixelate.c libgd/gd_arc.c libgd/gd_rotate.c libgd/gd_color.c \
- libgd/gd_transform.c libgd/gd_crop.c"
+ libgd/gd_transform.c libgd/gd_crop.c libgd/gd_interpolation.c libgd/gd_matrix.c"
dnl check for fabsf and floorf which are available since C99
AC_CHECK_FUNCS(fabsf floorf)