  Chiral extrapolation of the $X(3872)$ binding energy is investigated using
the modified Weinberg formulation of chiral effective field theory for the $D
\bar{D}^*$ scattering. Given its explicit renormalisability, this approach is
particularly useful to explore the interplay of the long- and short-range $D
\bar{D}^*$ forces in the $X(3872)$ from studying the light-quark (pion) mass
dependence of its binding energy. In particular, the parameter-free
leading-order calculation shows that the $X$-pole disappears for unphysical
large pion masses. On the other hand, without contradicting the naive
dimensional analysis, the higher-order pion-mass-dependent contact interaction
can change the slope of the binding energy at the physical point yielding the
opposite scenario of a stronger bound $X$ at pion masses larger than its
physical value. An important role of the pion dynamics and of the 3-body
$D\bar{D}\pi$ effects for chiral extrapolations of the $X$-pole is emphasised.
The results of the present study should be of practical value for the lattice
simulations since they provide a non-trivial connection between lattice points
at unphysical pion masses and the physical world.
