Initial Spring 2016 commit.

mk/os161.subdir.mk

@@ -0,0 +1,51 @@
+#
+# OS/161 build environment: recurse into subdirectories
+#
+# Usage:
+#    TOP=../..
+#    .include "$(TOP)/mk/os161.config.mk"
+#    [defs go here]
+#    .include "$(TOP)/mk/os161.subdir.mk"
+#    [any extra rules go here]
+#
+# Variables controlling this file:
+#
+# SUBDIRS			Directories to recurse into.
+# EXTRATARGETS			Additional targets to define.
+#
+# BASETARGETS may also be set to empty to suppress the usual targets.
+#
+# Note: SUBDIRS may contain .WAIT, which is treated as a parallelism
+# barrier like in the right hand side of a make rule.
+#
+# Further note: if combining os161.subdir.mk with other os161.*.mk
+# files (other than os161.config.mk), include os161.subdir.mk first;
+# then the ordering of things will cause recursion to happen
+# first. Also, .WAIT is inserted so that the recursion will finish
+# before anything else happens, which is almost always desirable.
+#
+
+BASETARGETS?=\
+	all depend install install-staging clean distclean tags \
+	cleandir stage dependall build rebuild fullrebuild
+
+# first, make each target depend on its -subdirs target,
+# and declare both PHONY.
+.for _T_ in $(BASETARGETS) $(EXTRATARGETS)
+$(_T_): $(_T_)-subdirs .WAIT
+.PHONY: $(_T_) $(_T_)-subdirs
+.endfor
+
+# now, make each -subdirs target depend on a rule for each subdir.
+.for _D_ in $(SUBDIRS)
+.for _T_ in $(BASETARGETS) $(EXTRATARGETS)
+.if "$(_D_)" == ".WAIT"
+$(_T_)-subdirs: .WAIT
+.else
+$(_T_)-subdirs: $(_T_)-subdirs-$(_D_)
+.PHONY: $(_T_)-subdirs-$(_D_)
+$(_T_)-subdirs-$(_D_):
+	(cd $(_D_) && $(MAKE) $(_T_))
+.endif
+.endfor
+.endfor