Implement Mario's suggestions:
- Clean up code replace merge algorithm with a function.
- Fix for_statement setting control variable to not a constant.
- Fix for_statement checking BY expression to get correct value for optimization
branch.

Thanks Mario.

include ../common.mk

lib_LIBRARIES = libabsyntax.a

libabsyntax_a_SOURCES = \
	absyntax.cc \
	visitor.cc