When resolving a line continuation $\<newline>, it normally resolves to $<space>, then to blank. There is a corner case in make 4.2.1 where it seems to resolve to the literal $ character instead. I have the following:
> cat tmp.mk $(info version: $(shell $(MAKE) --version)) $(info TEST: 1$\ 2) $(info TEST: [$(or \ ,$\ )]) all: @echo building $@ > make -f tmp.mk version: GNU Make 3.81 Copyright (C) 2006 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. This program built for x86_64-unknown-linux-gnu TEST: 12 TEST: [] building all > make2 -f tmp.mk version: GNU Make 4.2.1 Built for x86_64-pc-linux-gnu Copyright (C) 1988-2016 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. TEST: 12 TEST: [$] building all