While this is faster in every use case, it's especially useful when "cross-"compiling the kernel on one (fast) system and copying only the two .ko files to another, slower one where all the ZFS tools are already installed. It avoids "polluting" the build system with cutting-edge ZFS tools which may not even be needed there.
It's also more secure because it does not require "sudo" on build system where the "pseudo" install is run.
For SUBDIRS, automake generates the following comment in Makefile.am:
# This directory's subdirectories are mostly independent; you can cd
# into them and run 'make' without going through this Makefile.
# ...
$(am__recursive_targets):
While this is faster in every use case, it's especially useful when "cross-"compiling the kernel on one (fast) system and copying only the two .ko files to another, slower one where all the ZFS tools are already installed. It avoids "polluting" the build system with cutting-edge ZFS tools which may not even be needed there.
It's also more secure because it does not require "sudo" on build system where the "pseudo" install is run.
It's supported because
modules/is defined as a SUBDIRS: https://www.gnu.org/software/automake/manual/html_node/Subdirectories.htmlFor SUBDIRS, automake generates the following comment in Makefile.am: