ERROR: Nothing RPROVIDES 'libX' (but .../oe-core/meta-Y/recipes/images/Z-image.bb RDEPENDS on or otherwise requires it)

This error occurs when libX is also a output of package P that is specified to be install in target rootfs by Z-image.bb

IMAGE_INSTALL += "libX"

To fix this error, add below lines in P_git.bb

PACKAGES =+ "libX"

FILES_libX = "${libdir}/libX.so*"