* Remove setting of user flags
* Remove erroneous bundling of Eigen

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,15 +33,6 @@
 SET(EIGEN_VERSION_MINIMUM 3.1.2)
 SET(VIENNACL_VERSION_MINIMUM 1.5.0)
 
-# Store system's or distribution's C[XX]FLAGS.
-SET(SYSTEM_C_FLAGS "${CMAKE_C_FLAGS}")
-SET(SYSTEM_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-STRING(TOUPPER "${CMAKE_BUILD_TYPE}" BUILD_TYPE_UC)
-IF(NOT ("${BUILD_TYPE_UC}" STREQUAL "DISTRIBUTION"))
-	SET(CMAKE_C_FLAGS "")
-	SET(CMAKE_CXX_FLAGS "")
-ENDIF(NOT ("${BUILD_TYPE_UC}" STREQUAL "DISTRIBUTION"))
-
 # CCACHE
 OPTION(ENABLE_CCACHE "Enable ccache for compilation" ON)
 FIND_PACKAGE(CCache)
@@ -174,24 +165,6 @@
 	SET(COMPILER_WARNINGS "-Wall -Wno-unused-parameter -Wformat -Wformat-security -Wparentheses -Wshadow -Wno-unknown-pragmas -Wno-deprecated")
 ENDIF()
 
-IF(CMAKE_COMPILER_IS_GNUCXX)
-	SET(RELEASE_COMPILER_FLAGS "-fexpensive-optimizations -frerun-cse-after-loop -fcse-follow-jumps -finline-functions -fschedule-insns2 -fthread-jumps -fforce-addr -fstrength-reduce -funroll-loops")
-	IF (${MACHINE} MATCHES "x86_64" OR ${MACHINE} MATCHES "i686")
-		SET(RELEASE_COMPILER_FLAGS "${RELEASE_COMPILER_FLAGS} -mfpmath=sse")
-	ENDIF()
-ELSEIF(${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")
-	SET(RELEASE_COMPILER_FLAGS "-funroll-loops")
-ENDIF()
-SET(SWIG_CXX_COMPILER_FLAGS "-O0 -g")
-SET(CMAKE_C_FLAGS "${COMPILER_WARNINGS} ${CMAKE_C_FLAGS}")
-SET(CMAKE_CXX_FLAGS "${COMPILER_WARNINGS} ${CMAKE_CXX_FLAGS}")
-SET(CMAKE_C_FLAGS_RELEASE "-O3 ${RELEASE_COMPILER_FLAGS}")
-SET(CMAKE_CXX_FLAGS_RELEASE "-O3 ${RELEASE_COMPILER_FLAGS}")
-SET(CMAKE_C_FLAGS_DISTRIBUTION "-O2")
-SET(CMAKE_CXX_FLAGS_DISTRIBUTION "-O2")
-SET(CMAKE_C_FLAGS_DEBUG "-g")
-SET(CMAKE_CXX_FLAGS_DEBUG "-g")
-
 OPTION(ENABLE_COVERAGE "Enable code coverage" OFF)
 IF(ENABLE_COVERAGE)
 	IF(NOT CMAKE_COMPILER_IS_GNUCXX)
@@ -617,13 +590,6 @@
 	include(external/Eigen3)
 	LIST(APPEND SYSTEM_INCLUDES ${EIGEN_INCLUDE_DIR})
 ELSE()
-    # eigen3 bug related to aliasing operators and self-storing.
-    # TODO put in proper reference and version from when this is fixed
-    IF(${EIGEN_VERSION} VERSION_GREATER 3.2.90)
-        MESSAGE(WARNING "The system Eigen3 version ${EIGEN_VERSION} is buggy, manually bundling.")
-        include(external/Eigen3)
-    ENDIF()
-
 	LIST(APPEND SYSTEM_INCLUDES ${EIGEN_INCLUDE_DIR})
 ENDIF()
 
@@ -957,11 +923,6 @@
 # Respect system's or distribution's C[XX]FLAGS.
 OPTION(SWIG_WITH_SYSTEM_CFLAGS "Enable system's C[XX]FLAGS for compilation of swig-binaries" ON)
 
-IF(NOT ("${BUILD_TYPE_UC}" STREQUAL "DISTRIBUTION"))
-	SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${SYSTEM_C_FLAGS}")
-	SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${SYSTEM_CXX_FLAGS}")
-ENDIF(NOT ("${BUILD_TYPE_UC}" STREQUAL "DISTRIBUTION"))
-
 IF(SWIG_WITH_SYSTEM_CFLAGS)
 	SET(SWIG_CXX_COMPILER_FLAGS "${SWIG_CXX_COMPILER_FLAGS} ${SYSTEM_CXX_FLAGS}")
 ENDIF(SWIG_WITH_SYSTEM_CFLAGS)