Fix macOS dev environment

data/macos/common.env

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-if [ "$(uname -m)" = "arm64" ]; then
+if [ "$(uname -m)" = "arm64" ] || [ "$(uname -r)" = "20.1.0" ]; then
     MACOS_UNIVERSAL=1
 else
     MACOS_UNIVERSAL=0

data/macos/env.sh

@@ -21,9 +21,10 @@ unset CPPFLAGS
 if [ "${MACOS_UNIVERSAL}" -eq 1 ]; then
     export CFLAGS="${CFLAGS} -arch x86_64 -arch arm64"
     export LDFLAGS="${LDFLAGS} -arch x86_64 -arch arm64"
+    export MACOS_UNIVERSAL="true"
 else
-    export CFLAGS="${CFLAGS} -m${ARCH}"
-    export LDFLAGS="${LDFLAGS} -m${ARCH}"
+    export CFLAGS="${CFLAGS} -m64"
+    export LDFLAGS="${LDFLAGS} -m64"
 fi
 
 export CXXFLAGS="${CFLAGS} -stdlib=libc++ -Wno-unknown-pragmas -Wno-unused-private-field -Werror=auto-var-id"