Don't use -Werror because it makes the build too brittle when compiling with
leading-edge compiler versions.

Index: lmms-1.1.2/CMakeLists.txt
===================================================================
--- lmms-1.1.2/CMakeLists.txt
+++ lmms-1.1.2/CMakeLists.txt	2015-02-02 18:48:34.592414787 +0000
@@ -335,7 +335,7 @@
 # set compiler flags
 SET(WERROR_FLAGS "-Wall -Werror=unused-function -Wno-sign-compare -Wno-strict-overflow")
 IF(NOT LMMS_BUILD_APPLE)
-   SET(WERROR_FLAGS "${WERROR_FLAGS} -Werror")
+   #SET(WERROR_FLAGS "${WERROR_FLAGS} -Werror")
 ENDIF()
 
 # Due to a regression in gcc-4.8.X, we need to disable array-bounds check