index 0f2ba31..7e6ace8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -166,7 +166,6 @@ if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX)
 			message(FATAL_ERROR "GCC version must be at least 4.9 for regex support! See http://askubuntu.com/questions/428198/getting-installing-gcc-g-4-9-on-ubuntu and then set the environment variables CXX to g++-4.9 and CC to gcc-4.9. You may have to erase the build directory before re-running cmake.")
 		endif()
 	endif()
-	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -O2 -Wall -fvisibility=hidden -Wno-unused-but-set-variable")
 endif()
 
 # Clang
@@ -175,7 +174,6 @@ if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
 	if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.5)
 		message(FATAL_ERROR "Clang version must be at least 3.5 to avoid known bugs.")
 	endif()
-	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -O2 -fvisibility=hidden -Wall -Wextra -Wunused")
 endif()
 
 # Visual Studio
index d21069e..69f4f52 100644
--- a/c++lib/CMakeLists.txt
+++ b/c++lib/CMakeLists.txt
@@ -48,14 +48,6 @@ if(CMAKE_COMPILER_IS_GNUCXX)
   add_definitions("-Wall -g -Wno-unused-but-set-variable")
 endif()
 
-if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX)
-   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O2")
-endif()
-
-if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
-   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O2")
-endif()
-
 if(MSVC)
 	set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
 	set(MSVC_FLAGS
index b7869a9..91567ec 100644
--- a/frontend/gtkmm/CMakeLists.txt
+++ b/frontend/gtkmm/CMakeLists.txt
@@ -160,9 +160,6 @@ if (NOT INSTALL_TARGETS_ONLY)
 	install(FILES    ${CADABRA_IMAGES_DIR}/256x256/cadabra2-gtk.png   DESTINATION ${ICON_PREFIX}/share/icons/hicolor/256x256/apps)
 	install(FILES    ${CADABRA_IMAGES_DIR}/cadabra2-gtk.svg           DESTINATION ${ICON_PREFIX}/share/icons/hicolor/scalable/apps)
 	install(FILES    ${CADABRA_ROOT_DIR}/config/cadabra2-gtk.desktop  DESTINATION ${ICON_PREFIX}/share/applications)
-	install(CODE     "execute_process(COMMAND touch ${ICON_PREFIX_WITH_DESTDIR}/share/icons/hicolor/icon-theme.cache)")
-	install(CODE     "execute_process(COMMAND gtk-update-icon-cache-3.0 {ICON_PREFIX_WITH_DESTDIR}/share/icons/hicolor)")
-	install(CODE     "execute_process(COMMAND chmod go+r ${ICON_PREFIX_WITH_DESTDIR}/share/icons/hicolor/icon-theme.cache)")
 
 	# Install shared libraries on Windows. 
 	# https://stackoverflow.com/questions/32662215/how-do-you-install-gtk-3-0-on-windows