mkone and mkmany have no default rule for building lex targets,
though they do have rules for yacc, is there a reason?

Reference: /n/sources/patch/applied/lex-recipies
Date: Tue Dec  9 15:02:26 CET 2008
Signed-off-by: steve@quintile.net

--- /sys/src/cmd/mkone	Tue Dec  9 15:00:40 2008
+++ /sys/src/cmd/mkone	Tue Dec  9 15:00:37 2008
@@ -14,12 +14,18 @@
 %.$O:	%.c
 	$CC $CFLAGS $stem.c
 
+%.$O:	%.C
+	c++/$CC $CFLAGS $stem.C
+
 %.$O:	%.s
 	$AS $AFLAGS $stem.s
 
 y.tab.h y.tab.c:	$YFILES
 	$YACC $YFLAGS $prereq
 
+lex.yy.c:	$LFILES
+	$LEX $LFLAGS $prereq
+
 install:V:	$BIN/$TARG
 
 $BIN/$TARG:	$O.out
@@ -34,10 +40,10 @@
 		mk all
 
 nuke:V:
-	rm -f *.[$OS] [$OS].out y.tab.? y.debug y.output *.acid $TARG
+	rm -f *.[$OS] [$OS].out y.tab.? lex.yy.c y.debug y.output *.acid $TARG
 
 clean:V:
-	rm -f *.[$OS] [$OS].out y.tab.? y.debug y.output $TARG $CLEANFILES
+	rm -f *.[$OS] [$OS].out y.tab.? lex.yy.c y.debug y.output $TARG $CLEANFILES
 
 safeinstall:V: $O.out
 	test -e $BIN/$TARG && mv $BIN/$TARG $BIN/_$TARG
--- /sys/src/cmd/mkmany	Tue Dec  9 15:00:45 2008
+++ /sys/src/cmd/mkmany	Tue Dec  9 15:00:43 2008
@@ -16,12 +16,18 @@
 %.$O:	%.c
 	$CC $CFLAGS $stem.c
 
+%.$O:	%.C
+	c++/$CC $CFLAGS $stem.C
+
 %.$O:	%.s
 	$AS $AFLAGS $stem.s
 
 y.tab.h y.tab.c:	$YFILES
 	$YACC $YFLAGS $prereq
 
+lex.yy.c:	$LFILES
+	$LEX $LFLAGS $prereq
+
 %.install:V:	$BIN/%
 
 $BIN/%:	$O.%
@@ -60,10 +66,10 @@
 	update $UPDATEFLAGS $UPDATE
 
 nuke:V:
-	rm -f *.[$OS] y.tab.? y.debug y.output [$OS].* *.acid $TARG
+	rm -f *.[$OS] y.tab.? lex.yy.c y.debug y.output [$OS].* *.acid $TARG
 
 clean:V:
-	rm -f *.[$OS] *.a[$OS] y.tab.? y.debug y.output [$OS].* $TARG $CLEANFILES
+	rm -f *.[$OS] *.a[$OS] y.tab.? lex.yy.c y.debug y.output [$OS].* $TARG $CLEANFILES
 
 %.clean:V:
 	rm -f $stem.[$OS] [$OS].$stem $stem.acid $stem