[OE-core] [RFC PATCH] bitbake.conf: Start using parallel make for do_install

[Richard Purdie]

Most piece of software now support parallel make install. Enable
this by default using the value of PARALLEL_MAKE. In a similar way
to PARALLEL_MAKE we can disable this for broken recipes with:

PARALLEL_MAKEINST = ""

Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>
---
diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
index f18e35b..a1420cf 100644
--- a/meta/conf/bitbake.conf
+++ b/meta/conf/bitbake.conf
@@ -493,8 +493,11 @@ export TARGET_LDFLAGS = "-Wl,-O1 ${TARGET_LINK_HASH_STYLE}"
 # Which flags to leave by strip-flags() in bin/build/oebuild.sh ?
 ALLOWED_FLAGS = "-O -mcpu -march -pipe"
 
-# Pass parallel make options to the compile task only
+# Pass parallel make options to the compile task
 EXTRA_OEMAKE_prepend_task-compile = "${PARALLEL_MAKE} "
+PARALLEL_MAKEINST ??= "${PARALLEL_MAKE}"
+# Pass parallel make options to the install task
+EXTRA_OEMAKE_prepend_task-install = "${PARALLEL_MAKEINST} "
 
 ##################################################################
 # Optimization flags.