build: add buildinfo as single Makefile target

The prepare target was added some 11 years ago to build tools and
toolchain and was recently extended to  create buildinfo files for
reproducibility, meaning {feeds,version,config}.buildinfo.

As the buildbot workflow is more complex than the single prepare (kmod
feed insertion), prepare is only used to create those buildinfo files.
Running prepare however runs `target/compile` as well, taking time even
everything is already compiled.

Splitting this allows the buildbot to run only the `buildinfo` target
while others can still use the convenience feature `prepare`.

Signed-off-by: Paul Spooren <mail@aparcar.org>
(cherry picked from commit 6caf437652d858e5795ee16bdaf9f0436d2488f9)

diff --git a/Makefile b/Makefile
index f9b2bb563ee86b18a77d906906392b393c020d3e..ac447573f5882dfaaf143746839f9d32e37cf620 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -100,9 +100,12 @@ diffconfig: FORCE
        mkdir -p $(BIN_DIR)
        $(SCRIPT_DIR)/diffconfig.sh > $(BIN_DIR)/config.buildinfo
 
-prepare: .config $(tools/stamp-compile) $(toolchain/stamp-compile)
+buildinfo: FORCE
        $(_SINGLE)$(SUBMAKE) -r diffconfig buildversion feedsversion
 
+prepare: .config $(tools/stamp-compile) $(toolchain/stamp-compile)
+       $(_SINGLE)$(SUBMAKE) -r buildinfo
+
 world: prepare $(target/stamp-compile) $(package/stamp-compile) $(package/stamp-install) $(target/stamp-install) FORCE
        $(_SINGLE)$(SUBMAKE) -r package/index
        $(_SINGLE)$(SUBMAKE) -r checksum