diff --git a/dtool/Config.Linux.pp b/dtool/Config.Linux.pp
index acd81c4d9c..04668b5a0d 100644
--- a/dtool/Config.Linux.pp
+++ b/dtool/Config.Linux.pp
@@ -22,7 +22,7 @@
 #define IS_LINUX 1
 
 // What additional flags should we pass to interrogate?
-#if $[eq $[shell uname -i], x86_64] // if Linux is 64bit
+#if $[eq $[shell uname -m], x86_64] // if Linux is 64bit
   #define SYSTEM_IGATE_FLAGS -D_LP64
 #else
   #define SYSTEM_IGATE_FLAGS -D__i386__ -D__const=const -Dvolatile -Dmutable