fix mkfile, rename port to plan9

Author: Noam Preil

mkfile

@@ -5,7 +5,7 @@ HFILES=src/include/janet.h src/conf/janetconf.h
 JANET_PATH=/sys/lib/janet
 BIN=/$objtype/bin/
 DISABLED=PROCESSES EV NET ASSEMBLER FFI UTC_MKTIME REALPATH DYNAMIC_MODULES THREADS SYMLINKS LOCALES UMASK
-JANET_CONFIG=JANET_SINGLE_THREADED JANET_OS_NAME=9front JANET_ARCH_NAME=$objtype JANET_BUILD="9front" JANET_API='' JANET_NO_RETURN='' JANET_SIMPLE_GETLINE JANET_64 `{echo JANET_NO_^$DISABLED}
+JANET_CONFIG=JANET_SINGLE_THREADED JANET_OS_NAME=plan9 JANET_ARCH_NAME=$objtype JANET_API='' JANET_NO_RETURN='' JANET_SIMPLE_GETLINE JANET_64 `{echo JANET_NO_^$DISABLED} JANET_REDUCED_OS
 CFLAGS=-FTVBNcwp -D _POSIX_SOURCE -DJANET_PLAN9 -D_BSD_EXTENSION -D_LIMITS_EXTENSION -Isrc/include -Isrc/conf -I/sys/include/npe -Dtypestr=janettypestr -DJANET_API `{echo '-D'^$JANET_CONFIG}
 BOOT_CFLAGS=$CFLAGS -DJANET_BOOTSTRAP