[pkgsrc/trunk]: pkgsrc/mk Add support for MAKE_JOBS.pkgpath.

[dholland <dholland%pkgsrc.org@localhost>]

details:   https://anonhg.NetBSD.org/pkgsrc/rev/11b724f0ed3d
branches:  trunk
changeset: 331346:11b724f0ed3d
user:      dholland <dholland%pkgsrc.org@localhost>
date:      Sun Mar 17 03:59:11 2019 +0000

description:
Add support for MAKE_JOBS.pkgpath.

This allows setting MAKE_JOBS high and then setting e.g.
MAKE_JOBS.emulators/qemu=2 (or some such low value) to keep it from
thrashing during build.

Discussed/approved on tech-pkg two months ago and then I forgot to
actually commit it.

diffstat:

 mk/build/build.mk   |   4 +++-
 mk/defaults/mk.conf |  17 +++++++++++++----
 2 files changed, 16 insertions(+), 5 deletions(-)

diffs (60 lines):

diff -r def267f16959 -r 11b724f0ed3d mk/build/build.mk
--- a/mk/build/build.mk Sun Mar 17 01:17:23 2019 +0000
+++ b/mk/build/build.mk Sun Mar 17 03:59:11 2019 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: build.mk,v 1.24 2018/11/30 18:38:19 rillig Exp $
+# $NetBSD: build.mk,v 1.25 2019/03/17 03:59:11 dholland Exp $
 #
 # This file defines what happens in the build phase, excluding the
 # self-test, which is defined in test.mk.
@@ -55,6 +55,8 @@
 
 .if defined(MAKE_JOBS_SAFE) && !empty(MAKE_JOBS_SAFE:M[nN][oO])
 _MAKE_JOBS=    # nothing
+.elif defined(MAKE_JOBS.${PKGPATH})
+_MAKE_JOBS=    -j${MAKE_JOBS.${PKGPATH}}
 .elif defined(MAKE_JOBS)
 _MAKE_JOBS=    -j${MAKE_JOBS}
 .endif
diff -r def267f16959 -r 11b724f0ed3d mk/defaults/mk.conf
--- a/mk/defaults/mk.conf       Sun Mar 17 01:17:23 2019 +0000
+++ b/mk/defaults/mk.conf       Sun Mar 17 03:59:11 2019 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: mk.conf,v 1.300 2019/02/04 09:36:41 wiz Exp $
+# $NetBSD: mk.conf,v 1.301 2019/03/17 03:59:11 dholland Exp $
 #
 
 # This file provides default values for variables that may be overridden
@@ -50,20 +50,29 @@
 # Possible: -[0-9], --fast, --best (see gzip(1))
 # Default: -9
 
-#MAKE_JOBS=    3
+#MAKE_JOBS=                    3
+#MAKE_JOBS.category/dir=       2
 #      When defined, specifies the maximum number of jobs ("make -j")
 #      that are run in parallel when building packages with the default
 #      do-build action. MAKE_JOBS only affects the "build" target,
 #      neither "test" nor "install".
 #
+#      May be specified on a per-package basis; any package-specific
+#      value overrides the global setting. Package-specific settings are
+#      by source directory, not package name, as the circumstances that
+#      would lead one to make them are based on properties of sources.
+#
 #      Possible values: any positive integer. Useful values are around
 #      the number of processors on the machine.
 #
 #      Default value: (undefined)
 #
-#      Warning: This is experimental. Some packages will not build with
-#      this. Disabling this for an individual package can be done by
+#      Warning: Some packages will not build with this. Disabling
+#      parallel builds for an individual package can be done by
 #      setting MAKE_JOBS_SAFE=NO within the per package Makefile.
+#      When doing so, please include a comment indicating what went
+#      wrong so it can be crosschecked in the future after upstream
+#      changes.
 
 #OBJHOSTNAME=
 # use hostname-specific object directories, e.g.  work.amnesiac, work.localhost