diff --git a/src/imageutils/CMakeLists.txt b/src/imageutils/CMakeLists.txt
index 9681a4a..88257bd 100644
--- a/src/imageutils/CMakeLists.txt
+++ b/src/imageutils/CMakeLists.txt
@@ -11,7 +11,7 @@ include_directories(
 set( gvimageutils_SRCS imageutils.cpp jpegcontent.cpp scale.cpp transupp.c croppedqimage.cpp )
 
 if( HAVE_X86_MMX )
-  list( gvimageutils_SRCS APPEND _SRCS asm_scale.S )
+  list( APPEND gvimageutils_SRCS asm_scale.S )
 
   # Force to use C compiler for asm_scale.S instead of ASM
   # because it contains mixed code - ASM with C definitions