Behavior change related to MAKEFLAGS and recursive make in version 4.4.1

[Ouellette, Paul]

Hello,

Consider the following makefiles:
$ cat Makefile
MAKEFLAGS+=VAR=foo
all:
        $(info make VAR=$(VAR))
        @echo "env  VAR=$$VAR"
        $(MAKE) -C lib
$ cat lib/Makefile
all:
        @echo "env  VAR=$$VAR"
        $(info make VAR=$(VAR))

With GNU Make 4.4 and older, the output is:
$ make --no-print-directory
make VAR=foo
env  VAR=foo
make -C lib
make VAR=foo
env  VAR=foo

With GNU Make 4.4.1, the output is:
$ make --no-print-directory
make VAR=foo
env  VAR=
make -C lib
make VAR=
env  VAR=

I have a makefile that depends on VAR being set in the sub-make as in Make 4.4.
Was I depending on a bug or undefined behavior or is this a bug in Make 4.4.1?