diff --git a/mkfile b/mkfile
index 8f33ee09..c6f4937d 100644
--- a/mkfile
+++ b/mkfile
@@ -5,7 +5,8 @@ HFILES=src/include/janet.h src/conf/janetconf.h
 JANET_PATH=/sys/lib/janet
 BIN=/$objtype/bin/
 DISABLED=PROCESSES EV NET ASSEMBLER FFI UTC_MKTIME REALPATH DYNAMIC_MODULES THREADS SYMLINKS LOCALES UMASK
-JANET_CONFIG=JANET_SINGLE_THREADED JANET_OS_NAME=plan9 JANET_ARCH_NAME=$objtype JANET_API='' JANET_NO_RETURN='' JANET_SIMPLE_GETLINE JANET_64 `{echo JANET_NO_^$DISABLED} JANET_REDUCED_OS
+JANET_CONFIG=JANET_SINGLE_THREADED JANET_OS_NAME=plan9 JANET_ARCH_NAME=$objtype JANET_API='' JANET_NO_RETURN='' JANET_SIMPLE_GETLINE `{echo JANET_NO_^$DISABLED} JANET_REDUCED_OS PLAN9_`{echo -n $objtype}
+
 CFLAGS=-FTVBNcwp -D _POSIX_SOURCE -DJANET_PLAN9 -D_BSD_EXTENSION -D_LIMITS_EXTENSION -Isrc/include -Isrc/conf -I/sys/include/npe -Dtypestr=janettypestr -DJANET_API `{echo '-D'^$JANET_CONFIG}
 BOOT_CFLAGS=$CFLAGS -DJANET_BOOTSTRAP
 
diff --git a/src/include/janet.h b/src/include/janet.h
index 0401bf0e..9879db64 100644
--- a/src/include/janet.h
+++ b/src/include/janet.h
@@ -113,8 +113,6 @@ extern "C" {
 #endif
 
 /* Check 64-bit vs 32-bit */
-#ifndef JANET_64
-#ifndef JANET_32
 #if ((defined(__x86_64__) || defined(_M_X64)) \
      && (defined(JANET_POSIX) || defined(JANET_WINDOWS))) \
     || (defined(_WIN64)) /* Windows 64 bit */ \
@@ -123,6 +121,7 @@ extern "C" {
     || (defined(__sparc__) && defined(__arch64__) || defined (__sparcv9)) /* BE */ \
     || defined(__s390x__) /* S390 64-bit (BE) */ \
     || (defined(__ppc64__) || defined(__PPC64__)) \
+    || defined(PLAN9_arm64) || defined(PLAN9_amd64) \
     || defined(__aarch64__) /* ARM 64-bit */ \
     || (defined(__riscv) && (__riscv_xlen == 64)) /* RISC-V 64-bit */ \
     || defined(__loongarch64) /* LoongArch64 64-bit */
@@ -130,8 +129,6 @@ extern "C" {
 #else
 #define JANET_32 1
 #endif
-#endif
-#endif
 
 /* Check big endian */
 #if defined(__LITTLE_ENDIAN__) || \