buildsystem: add possibility to move the build paths outside the git …

[InuSasha]

…tree

builds can be placed on different (faster) disk.
The normal behavior unchanged. To change the path only add BUILD_ROOT=/build-dev in your .libreelec/options
For use with multiple git-workspaces BUILD_ROOT=/build-dev/$(basename $ROOT) is better.

tested with: generic & rpi2 builds (incl. all addons)

[vpeter4]

This is ridiculous. Just put whole LE on this faster disk and you are done. Seems LE is folowing Kodi development path lately: "let's change things just because we can".

[antonlacon]

Does PR3147 meet your needs?

[vpeter4]

My special needs/requirements are taking care with my own build. But I don't push them to LE just to make my life easier. There are lot of commits lately which would not be even considered to be included few years back. But who am I to judge. Seems messing with build system must be really fun :) Even if not broken.

[MilhouseVH]

While I do agree this requirement is niche, it is consistent with previous changes (see #2348), so I would be inclined to accept this change but possibly not in the current form - I'd suggest introducing a BUILD_DIR override (either from the command line, or $HOME/.libreelec/options etc.).

This means in config/path, adding:

BUILD_ROOT=${BUILD_DIR:-${ROOT}}

and then in config/path, changing:

-BUILD=$ROOT/$BUILD_BASE.$DISTRONAME-${DEVICE:-$PROJECT}.$TARGET_ARCH-$LIBREELEC_VERSION
+BUILD=$BUILD_ROOT/$BUILD_BASE.$DISTRONAME-${DEVICE:-$PROJECT}.$TARGET_ARCH-$LIBREELEC_VERSION
 if [ "$LIBREELEC_VERSION" = "devel" ] ; then
-  BUILD=$ROOT/$BUILD_BASE.$DISTRONAME-${DEVICE:-$PROJECT}.$TARGET_ARCH-$OS_VERSION-$LIBREELEC_VERSION
+  BUILD=$BUILD_ROOT/$BUILD_BASE.$DISTRONAME-${DEVICE:-$PROJECT}.$TARGET_ARCH-$OS_VERSION-$LIBREELEC_VERSION
 fi

As an aside, I'm really not sure what value there is in BUILD_BASE=build and think that could be dropped entirely, so that we just hard-code build. where necessary... so we could just have, at the top of config/path, something like...

PACKAGES=packages
SOURCES=${SOURCES_DIR:-${ROOT}/sources}
BUILD_ROOT=${BUILD_DIR:-${ROOT}}
TARGET_IMG=${TARGET_DIR:-${ROOT}/target}

[MilhouseVH]

Note that @antonlacon has identified some other areas where ${ROOT}/${BUILD_BASE} is used (ie. scripts/build, scripts/clean) which may need addressing in this PR (and could justify a $BUILD_BASE variable for build.)...

[InuSasha]

I take a look, to adjust the change. I will compare to SOURCE_DIR and TARGET_DIR

I am a bit paranoid, after a disk crash and use only backuped or raids for working paths. These are slow, but more protected. But all run/build-paths on fast constructions.

[InuSasha]

@MilhouseVH i switchted to your BASE_PREFIXsuggestion.
Also i added -e to the shebang -> no need for die

[dhewg]

Leftover?

[InuSasha]

nope. possible name for a symlink to right location

[dhewg]

What symlink? AFAICS nothing uses /builds and this patch gets rid of the need to symlink anything?

[InuSasha]

when you moved the build-root outside, you may want to access it fast.
so a symlink builds to the new location will be fine ;)

[dhewg]

The clean targets in the toplevel Makefile need changes too

[InuSasha]

this will be difficult: because we do not know, if we can delete all at the new location.
Everyone who move it outside the default location, has to cleanup it self.

[dhewg]

I don't know why this should be ridiculous, but I'm using this ;)

Usecase: fast box with lots of RAM and just a SSD. Building the whole of LE on that doesn't exactly go easy on the drive and wears it out too fast. So I build it on a 30gb ramdisk. And no, I don't want to move my git tree there ;)

[dhewg]

this will be difficult: because we do not know, if we can delete all at the new location.
Everyone who move it outside the default location, has to cleanup it self.

Good point.

Overall, this fits in nicely with e.g. SOURCES_DIR and TARGET_DIR, so I don't see a reason for not merging it

[MilhouseVH]

Let's see what breaks... 😄