Arch Linux

Description:
With make 4.2-1, running "make -j4" with any Makefile that invokes child instances will print the following warning in each and every child:

make[1]: warning: -jN forced in submake: disabling jobserver mode.

Additional info:
* package version(s)
make 4.2-4

Steps to reproduce:
Try the following toplevel Makefile:

all: target1 target2

target1:
echo Makefile invoked from toplevel directory

target2:
${MAKE} ${MFLAGS} -f subdir/Makefile

With the following subdir/Makefile:

all:
echo "Make invoked from subdirectory."

Running "make -j4" with 4.1-4:

echo Makefile invoked from toplevel directory
Makefile invoked from toplevel directory
make -f subdir/Makefile
make[1]: Entering directory '/home/john/tmp'
echo "Make invoked from subdirectory."
Make invoked from subdirectory.
make[1]: Leaving directory '/home/john/tmp'

Running "make -j4" with 4.2-1:

echo Makefile invoked from toplevel directory
make -j4 --jobserver-auth=3,4 -f subdir/Makefile
Makefile invoked from toplevel directory
make[1]: warning: -jN forced in submake: disabling jobserver mode.
make[1]: Entering directory '/home/john/tmp'
echo "Make invoked from subdirectory."
Make invoked from subdirectory.