diff --git a/src/rt/rust_android_dummy.c b/src/rt/rust_android_dummy.c
index 9d91b995073..c322dc6706f 100644
--- a/src/rt/rust_android_dummy.c
+++ b/src/rt/rust_android_dummy.c
@@ -28,6 +28,11 @@ double log2( double n )
     return log( n ) / log( 2 );
 }
 
+double exp10( double x )
+{
+    return pow( 10, x );
+}
+
 void telldir()
 {
 }