update mkfile to be more in line with build.sh

mkfile

@@ -1,10 +1,9 @@
 </$objtype/mkfile
 
-TARG=assembler debugger emulator
-USM=`{walk -f projects/ | grep '\.usm$' | grep -v blank.usm | grep -v asma.usm}
+TARG=bin/debugger bin/uxnasm bin/uxnemu
+USM=`{walk -f projects/ | grep '\.usm$' | grep -v blank.usm}
 ROM=${USM:%.usm=%.rom}
 CFLAGS=$CFLAGS -I/sys/include/npe
-BIN=/$objtype/bin/uxn
 HFILES=\
 	/sys/include/npe/stdio.h\
 	src/devices/apu.h\
@@ -12,13 +11,14 @@ HFILES=\
 	src/devices/ppu.h\
 	src/uxn.h\
 
-CLEANFILES=${TARG:%=bin/%} `{echo $ROM | sed 's,([^ /]+/)+,bin/,g'}
+CLEANFILES=$TARG $ROM
 
 default:V: all
 
-all:V: ${TARG:%=bin/%} $ROM
+all:V: bin $TARG $ROM
 
-</sys/src/cmd/mkmany
+bin:
+	mkdir -p bin
 
 /sys/include/npe/stdio.h:
 	hget https://git.sr.ht/~ft/npe/archive/master.tar.gz | tar xz &&
@@ -26,26 +26,31 @@ all:V: ${TARG:%=bin/%} $ROM
 	mk install &&
 	rm -r npe-master
 
-%.rom: %.usm bin/assembler
-	bin/assembler $stem.usm $target && cp $target bin/
+%.rom:Q: %.usm bin/uxnasm
+	bin/uxnasm $stem.usm $target >/dev/null
 
-bin/assembler:Q: $O.assembler
-	mkdir -p bin && cp $prereq $target
+bin/debugger: debugger.$O uxn.$O
+	$LD -o $target $prereq
 
-bin/debugger:Q: $O.debugger
-	mkdir -p bin && cp $prereq $target
+bin/uxnasm: assembler.$O
+	$LD -o $target $prereq
 
-bin/emulator:Q: $O.emulator
-	mkdir -p bin && cp $prereq $target
-
-$O.assembler: assembler.$O
-
-$O.debugger: debugger.$O uxn.$O
-
-$O.emulator: emulator.$O apu.$O mpu.$O ppu.$O uxn.$O
+bin/uxnemu: emulator.$O apu.$O mpu.$O ppu.$O uxn.$O
+	$LD -o $target $prereq
 
 (assembler|debugger|emulator|uxn)\.$O:R: src/\1.c
 	$CC $CFLAGS -Isrc -o $target src/$stem1.c
 
 (apu|mpu|ppu)\.$O:R: src/devices/\1.c
 	$CC $CFLAGS -Isrc -o $target src/devices/$stem1.c
+
+nuke:V: clean
+
+clean:V:
+	rm -f *.[$OS] [$OS].??* $TARG $CLEANFILES
+
+%.clean:V:
+	rm -f $stem.[$OS] [$OS].$stem $stem
+
+install:QV: all
+	exit 'Sorry, there is no install rule yet'