commit 243e5701685cc72d46f093967d45c6044286a630
author Jerome Forissier <jerome.forissier@linaro.org> Fri Aug 19 13:12:24 2022 +0000
committer Jérôme Forissier <jerome@forissier.org> Mon Aug 22 13:35:31 2022 +0200
tree 1e55575ff7afa9dac64326e50eff48f7b4709bad
parent 80164983242b9434e4d1a2941b8fa854499bd9e2

common.mk: buildroot: force make -j1 in buildroot when not per-package

Buildroot parallel build is allowed when BR2_PER_PACKAGE_DIRECTORIES is
'y', see commit e9bff1c86e93 ("common.mk: buildroot: enable top-level
parallel build"). When disabled, Buildroot is not supposed to spawn
several make jobs simultaneously. However for some reason it seems it
can happen, see the IBART failure at [1]. The steps:
 >>> optee_client_ext 1.0 Fixing libtool files
and:
 >>> pcsc-lite 1.9.4 Fixing libtool files
...seem to be running simultaneously and touching the same path (since
per-package is disabled), which results in:
 mv: cannot stat '/home/optee/devel/qemu/out-br/host/arm-buildroot-linux-gnueabihf/sysroot/usr/lib/libpcsclite.la.fixed': No such file or directory
 package/pkg-generic.mk:331: recipe for target '/home/optee/devel/qemu/out-br/build/pcsc-lite-1.9.4/.stamp_staging_installed' failed

I confirmed the fact by adding a 'sleep 5' after "Fixing libtool files"
in package/pkg-generic.mk, as well as a 'ps -ef | grep sleep | grep -v
grep || :' just before the sleep. Then when building with
'make -j32 BR2_PER_PACKAGE_DIRECTORIES=n' (32 core machine) the 'sleep 5'
is displayed occasionally.

To avoid that, let's explicitly invoke make with -j1 when
BR2_PER_PACKAGE_DIRECTORIES is disabled.

Link: [1] https://optee.mooo.com:5000/logs/OP-TEE/optee_os/5487/1027234243/9147c347fb53612f62bf7de1c17e47a246d61ef2#02-qemu-build line 16398:
Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>