docs: bump minimal GNU Make version to 3.81
Since 2014, you can't successfully build kernels with GNU Make version
3.80. Example errors:
$ git describe
v4.11
$ make --version | head -1
GNU Make 3.80
$ make defconfig
HOSTCC scripts/basic/fixdep
scripts/Makefile.host:135: *** missing separator. Stop.
make: *** [defconfig] Error 2
$ make ARCH=arm64 help
arch/arm64/Makefile:43: *** unterminated call to function `warning': missing `)'. Stop.
$ make help >/dev/null
./Documentation/Makefile.sphinx:25: Extraneous text after `else' directive
./Documentation/Makefile.sphinx:31: *** only one `else' per conditional. Stop.
make: *** [help] Error 2
The first breakage was introduced by commit c8589d1e9e01 ("kbuild:
handle multi-objs dependency appropriately"). Since then (i.e. v3.18),
GNU Make 3.80 has not been able to compile the kernel, but nobody has
ever complained aboutt (or noticed) it.
Even GNU Make 3.81 is more than 10 years old. It would not hurt to
match the documentation with reality instead of fixing makefiles.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed