diff --git a/Android.bp b/Android.bp
index 44d7092..43982e4 100644
--- a/Android.bp
+++ b/Android.bp
@@ -11,7 +11,6 @@
 prebuilt_build_tool {
     name: "bison",
     deps: ["common/bison/**/*"],
-    export_to_make_var: "BISON",
     target: {
         darwin: {
             src: "darwin-x86/bin/bison",
@@ -26,7 +25,6 @@
 
 prebuilt_build_tool {
     name: "flex",
-    export_to_make_var: "LEX",
     target: {
         darwin: {
             src: "darwin-x86/bin/flex",
@@ -39,7 +37,6 @@
 
 prebuilt_build_tool {
     name: "m4",
-    export_to_make_var: "M4",
     target: {
         darwin: {
             src: "darwin-x86/bin/m4",