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Diffstat (limited to 'build-aux/Makefile.once.head/00-var.mk')
| -rw-r--r-- | build-aux/Makefile.once.head/00-var.mk | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/build-aux/Makefile.once.head/00-var.mk b/build-aux/Makefile.once.head/00-var.mk new file mode 100644 index 0000000000..7c9e6ffe55 --- /dev/null +++ b/build-aux/Makefile.once.head/00-var.mk @@ -0,0 +1,36 @@ +# Copyright (C) 2016-2017 Luke Shumaker +# +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU Affero General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU Affero General Public License for more details. +# +# You should have received a copy of the GNU Affero General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +mod.var.description = Depend on the values of variables +define mod.var.doc +# Inputs: +# (user-defined) +# Outputs: +# Target : `$(outdir)/.var.%` +# Directory variable: `at.targets` +# Directory variable: `var.` +# +# It's a well-known secret that many files generated by a Makefile vary with +# the values of particular variables, but that GNU Make can't track these +# dependencies. Well, with some cleverness, it actually can! +# +# With this module, to depend on the value of a variable, depend on +# `$(outdir)/.var.VARNAME`, or `$(var.)VARNAME` for short. +endef +mod.var.doc := $(value mod.var.doc) + +var. = $(patsubst ./%,%,$(outdir)/.var.) + +.PHONY: _var.FORCE |