With the combination:

export G4VIS_BUILD_DAWNFILE_DRIVER=1
export G4VIS_BUILD_OPENGLX_DRIVER=1
export G4VIS_BUILD_RAYX_DRIVER=1
export G4VIS_BUILD_OPENGLXM_DRIVER=1
export G4VIS_BUILD_VRML_DRIVER=1

export G4VIS_USE_DAWNFILE=1
export G4VIS_USE_OPENGLX=1
export G4VIS_USE_RAYX=1
export G4VIS_USE_OPENGLXM=1
export G4VIS_USE_VRML=1

the precompiler variables G4INTY_BUILD_XT and G4INTY_USE_XT are not
set. Therefore the Xt-routines are not compiled and the linker (later
on) does not find G4Xt::getInstance() and other routines.

I think, in the Makefile the line

	include $(G4INSTALL)/config/G4VIS_BUILD.gmk

is missing to set these variables correctly.