[PATCH v2 2/4] Documentation/Makefile: avoid multiple patterns when generating one file

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

From: Paul Smith <psmith@gnu.org>

A GNU make pattern rule with multiple targets has always meant that
a single invocation of the recipe will build all the targets.
However in older versions of GNU make a recipe that did not really
build all the targets would be tolerated.

Starting with GNU make 4.4 this behavior is deprecated and pattern
rules are expected to generate files to match all the patterns.
If not all targets are created then GNU make will not consider any
target up to date and will re-run the recipe when it is run again.

I.e. a command like:

	make -C Documentation git-am.1

Will never be satisfied that "git-am.1" has been made, because we
didn't also make "git-am.5" and "git-am.7", as the warning it'll emit
indicates:

	$ make -C Documentation git-am.1
	[...]
	    XMLTO git-am.1
	Makefile:355: warning: pattern recipe did not update peer target 'git-am.7'.
	Makefile:355: warning: pattern recipe did not update peer target 'git-am.5'.

Modify Documentation/Makefile to split the man page-creating pattern
rule into a separate pattern rule for each pattern. This requires a
small amount of copy/pasting, but due to splitting out the "DOC_MANN"
in the preceding commit it's not too bad.

Reported-by: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Paul Smith <psmith@gnu.org>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Documentation/Makefile | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Documentation/Makefile b/Documentation/Makefile
index d239f6751f0..89929e3d60b 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -356,7 +356,11 @@ manpage-base-url.xsl: manpage-base-url.xsl.in
 	$(QUIET_GEN)sed "s|@@MAN_BASE_URL@@|$(MAN_BASE_URL)|" $< > $@
 
 $(DOC_MANN): manpage-base-url.xsl $(wildcard manpage*.xsl)
-%.1 %.5 %.7 : %.xml
+%.1 : %.xml
+	$(QUIET_XMLTO)$(XMLTO) -m $(MANPAGE_XSL) $(XMLTO_EXTRA) man $<
+%.5 : %.xml
+	$(QUIET_XMLTO)$(XMLTO) -m $(MANPAGE_XSL) $(XMLTO_EXTRA) man $<
+%.7 : %.xml
 	$(QUIET_XMLTO)$(XMLTO) -m $(MANPAGE_XSL) $(XMLTO_EXTRA) man $<
 
 %.xml : %.txt $(ASCIIDOC_DEPS)
-- 
2.39.0.rc0.993.g0c499e58e3b