Documentation/process/changes.rst notes the minimal GNU Make version, but it is not checked anywhere. We could check $(MAKE_VERSION), but another simple way is to check $(.FEATURES) since the feature list always grows. GNU Make 3.81 expands $(.FEATURES) to: target-specific order-only second-expansion else-if archives jobserver check-symlink GNU Make 3.82 expands $(.FEATURES) to: target-specific order-only second-expansion else-if shortest-stem undefine archives jobserver check-symlink To ensure Make >= 3.82, you can check either 'shortest-stem' or 'undefine'. This way is not always possible. For example, Make 4.0 through 4.2 have the same set of $(.FEATURES). At that point, we will need to come up with a different approach. Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx> Reviewed-by: Nicolas Schier <nicolas@xxxxxxxxx> --- Changes in v4: - Show the minumal required version in the error message - More commit description Changes in v3: - Check the version in a different way Makefile | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Makefile b/Makefile index 591485152a95..7f831e63b39b 100644 --- a/Makefile +++ b/Makefile @@ -11,6 +11,10 @@ NAME = Hurr durr I'ma ninja sloth # Comments in this file are targeted only to the developer, do not # expect to learn how to build the kernel reading this file. +ifeq ($(filter undefine,$(.FEATURES)),) +$(error GNU Make >= 3.82 is required. Your Make version is $(MAKE_VERSION)) +endif + $(if $(filter __%, $(MAKECMDGOALS)), \ $(error targets prefixed with '__' are only for internal use)) -- 2.34.1
