Add check whether the same constant var_external variable is initialised with two (or more) different constant values.
include ../../common.mk
lib_LIBRARIES = libstage4_iec.a
libstage4_iec_a_SOURCES = generate_iec.cc
libstage4_iec_a_LIBADD = ../stage4.o
libstage4_iec_a_CPPFLAGS = -I../../../absyntax