-LDFLAGS = $(COMMON_FLAGS)
-CFLAGS = -std=c99 -D_ISOC99_SOURCE -I. -I../include -I../common -I../zlib -I../uart -I/opt/local/include -I../liblua -Wall $(COMMON_FLAGS) -g -O3
-CXXFLAGS = -I../include -Wall -O3
+LDFLAGS = $(ENV_LDFLAGS)
+CFLAGS = $(ENV_CFLAGS) -std=c99 -D_ISOC99_SOURCE -I. -I../include -I../common -I../zlib -I../uart -I/opt/local/include -I../liblua -Wall -g -O3
+CXXFLAGS = -I../include -I../uart -Wall -O3