Bump dxcommon to fix builds using --disable-dependency-tracking.
Some build rules were inadvertently depending on directory creation that
happens as a side effect of depfiles generation. This does not happen
when configuring with --disable-dependency-tracking, leading to issues
with VPATH builds.
Failures are easily observed with a command like
make DISTCHECK_CONFIGURE_FLAGS=--disable-dependency-tracking distcheck
Using parallel make can hide problems since it seems Automake also
generates make rules that incidentally create these directories.