Add support for parsing of REF_TO keyword (defined in IEC61131-3 v3). This support is currently inactive (in flex) until we get to add C code generation later on.
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