build: use installbsd instead of install on AIX

Even in mkmk.sh.

dist/buildmk

@@ -2,5 +2,5 @@
 
 # run this in the src directory
 . ../src/mkenv
-export SYSNAME OBJTYPE
+export SYSNAME OBJTYPE INSTALL
 sh -x mkmk.sh

src/mk.AIX-power

@@ -1,2 +0,0 @@
-INSTALL=installbsd
-

src/mkenv

@@ -20,3 +20,4 @@ OBJTYPE=`(uname -m -p 2>/dev/null || uname -m) | sed '
 	s;.*aarch64.*;arm64;
 	s;.*arm64.*;arm64;
 '`
+INSTALL=`[ $(uname) = AIX ] && echo installbsd || echo install`

src/mkfile

@@ -35,6 +35,7 @@ mkmk.sh:VD:
 			echo cd ..
 		done
 	) | sed '
+		s/'$INSTALL'/$INSTALL/g
 		s/'$SYSNAME'/$SYSNAME/g
 		s/'$OBJTYPE'/$OBJTYPE/g
 		s;'$PLAN9';$PLAN9;g

src/mkhdr

@@ -11,7 +11,6 @@ CC=9c
 LD=9l
 AS=9a
 AR=9ar
-INSTALL=install
 CFLAGS=
 LDFLAGS=
 AFLAGS=
@@ -24,5 +23,3 @@ LIB=
 SHORTLIB=9
 
 <|cat $PLAN9/config 2>/dev/null || true
-<|cat $PLAN9/src/mk.$SYSNAME-$OBJTYPE 2>/dev/null || true
-

src/mkmk.sh

@@ -209,5 +209,5 @@ echo cd `pwd`
 9c  word.c
 9c  unix.c
 9l -o o.mk arc.o archive.o bufblock.o env.o file.o graph.o job.o lex.o main.o match.o mk.o parse.o recipe.o rc.o rule.o run.o sh.o shell.o shprint.o symtab.o var.o varsub.o word.o unix.o 
-install o.mk $PLAN9/bin/mk
+$INSTALL o.mk $PLAN9/bin/mk
 cd ..