diff --git a/CMakeModules/LibWebRTCPrefix.cmake b/CMakeModules/LibWebRTCPrefix.cmake
index 8cff0d1..d721c70 100644
--- a/CMakeModules/LibWebRTCPrefix.cmake
+++ b/CMakeModules/LibWebRTCPrefix.cmake
@@ -39,10 +39,11 @@ else (WIN32)
   set(PREFIX_NEWLINE \n)
 endif (WIN32)
 
-file(WRITE ${PREFIX_FILENAME} ${PREFIX_HEADER}${PREFIX_NEWLINE})
-file(APPEND ${PREFIX_FILENAME} ${PREFIX_COMMAND}\ PATH=${WEBRTC_PATH}${PREFIX_NEWLINE})
-file(APPEND ${PREFIX_FILENAME} ${PREFIX_COMMAND}\ PYTHONPATH=${CHROMIUM_PYTHONPATH}${PREFIX_NEWLINE})
-file(APPEND ${PREFIX_FILENAME} ${PREFIX_COMMAND}\ DEPOT_TOOLS_WIN_TOOLCHAIN=0${PREFIX_NEWLINE})
-file(APPEND ${PREFIX_FILENAME} ${PREFIX_COMMAND}\ DEPOT_TOOLS_UPDATE=0${PREFIX_NEWLINE})
-file(APPEND ${PREFIX_FILENAME} ${PREFIX_COMMAND}\ CHROME_HEADLESS=1${PREFIX_NEWLINE})
-file(APPEND ${PREFIX_FILENAME} ${PREFIX_EVAL}${PREFIX_NEWLINE})
+file(WRITE ${PREFIX_FILENAME} "${PREFIX_HEADER}
+${PREFIX_COMMAND} PATH=${WEBRTC_PATH}
+${PREFIX_COMMAND} PYTHONPATH=${CHROMIUM_PYTHONPATH}
+${PREFIX_COMMAND} DEPOT_TOOLS_WIN_TOOLCHAIN=0
+${PREFIX_COMMAND} DEPOT_TOOLS_UPDATE=0
+${PREFIX_COMMAND} CHROME_HEADLESS=1
+${PREFIX_EVAL}
+")