build-sys: use a generic TEXI2MAN rule

The recipe for making a man page from .texi is duplicated several
times over.  Capture it in suitable pattern rules instead.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20170113144135.5150-20-marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

Makefile

@@ -552,35 +552,11 @@ qemu-img-cmds.texi: $(SRC_PATH)/qemu-img-cmds.hx $(SRC_PATH)/scripts/hxtool
 	$(call quiet-command,sh $(SRC_PATH)/scripts/hxtool -t < $< > $@,"GEN","$@")
 
 qemu.1: qemu-doc.texi qemu-options.texi qemu-monitor.texi qemu-monitor-info.texi
-	$(call quiet-command, \
-	  perl -Ww -- $(SRC_PATH)/scripts/texi2pod.pl $< qemu.pod && \
-	  $(POD2MAN) --section=1 --center=" " --release=" " qemu.pod > $@, \
-	  "GEN","$@")
 qemu.1: qemu-option-trace.texi
-
 qemu-img.1: qemu-img.texi qemu-option-trace.texi qemu-img-cmds.texi
-	$(call quiet-command, \
-	  perl -Ww -- $(SRC_PATH)/scripts/texi2pod.pl $< qemu-img.pod && \
-	  $(POD2MAN) --section=1 --center=" " --release=" " qemu-img.pod > $@, \
-	  "GEN","$@")
-
 fsdev/virtfs-proxy-helper.1: fsdev/virtfs-proxy-helper.texi
-	$(call quiet-command, \
-	  perl -Ww -- $(SRC_PATH)/scripts/texi2pod.pl $< fsdev/virtfs-proxy-helper.pod && \
-	  $(POD2MAN) --section=1 --center=" " --release=" " fsdev/virtfs-proxy-helper.pod > $@, \
-	  "GEN","$@")
-
 qemu-nbd.8: qemu-nbd.texi qemu-option-trace.texi
-	$(call quiet-command, \
-	  perl -Ww -- $(SRC_PATH)/scripts/texi2pod.pl $< qemu-nbd.pod && \
-	  $(POD2MAN) --section=8 --center=" " --release=" " qemu-nbd.pod > $@, \
-	  "GEN","$@")
-
 qemu-ga.8: qemu-ga.texi
-	$(call quiet-command, \
-	  perl -Ww -- $(SRC_PATH)/scripts/texi2pod.pl $< qemu-ga.pod && \
-	  $(POD2MAN) --section=8 --center=" " --release=" " qemu-ga.pod > $@, \
-	  "GEN","$@")
 
 html: qemu-doc.html
 info: qemu-doc.info

rules.mak

@@ -363,3 +363,13 @@ define unnest-vars
         $(eval -include $(patsubst %.o,%.d,$(patsubst %.mo,%.d,$($v))))
         $(eval $v := $(filter-out %/,$($v))))
 endef
+
+TEXI2MAN = $(call quiet-command, \
+	perl -Ww -- $(SRC_PATH)/scripts/texi2pod.pl $< $@.pod && \
+	$(POD2MAN) --section=$(subst .,,$(suffix $@)) --center=" " --release=" " $@.pod > $@, \
+	"GEN","$@")
+
+%.1:
+	$(call TEXI2MAN)
+%.8:
+	$(call TEXI2MAN)