Fix typos in references to OS_ARCH, OS_NAME

build_odin.sh

@@ -61,7 +61,7 @@ OpenBSD)
 	LDFLAGS="$LDFLAGS $($LLVM_CONFIG --libs core native --system-libs)"
 	;;
 *)
-	error "Platform \"OS_NAME\" unsupported"
+	error "Platform \"$OS_NAME\" unsupported"
 	;;
 esac
 
@@ -74,7 +74,7 @@ build_odin() {
 		EXTRAFLAGS="-O3"
 		;;
 	release-native)
-		if [ "OS_ARCH" == "arm64" ]; then
+		if [ "$OS_ARCH" == "arm64" ]; then
 			# Use preferred flag for Arm (ie arm64 / aarch64 / etc)
 			EXTRAFLAGS="-O3 -mcpu=native"
 		else