diff --git a/CMake/variants/GNUCXX11.cmake b/CMake/variants/GNUCXX11.cmake
index 427fd5e01d4ac03c34aeaa83a93884fde7b19728..a87d417a25683b9a6525aaad203fd308d17d790c 100644
--- a/CMake/variants/GNUCXX11.cmake
+++ b/CMake/variants/GNUCXX11.cmake
@@ -21,7 +21,7 @@ set(GNUCXX11_C_FLAGS_DEBUG    "-g")
 set(GNUCXX11_C_FLAGS_OPT      "-g -O2")
 set(GNUCXX11_C_FLAGS_OPT3     "-g -O3")
 set(GNUCXX11_C_FLAGS_OPTARCH  "-g -O3 -march=native")
-set(GNUCXX11_CXX_FLAGS        "-std=c++11 -W -Wall -Woverloaded-virtual -Wno-unknown-pragmas")
+set(GNUCXX11_CXX_FLAGS        "-std=c++11 -fext-numeric-literals -W -Wall -Woverloaded-virtual -Wno-unknown-pragmas")
 set(GNUCXX11_CXX_FLAGS_DEBUG  "-g")
 set(GNUCXX11_CXX_FLAGS_OPT    "-g -O2")
 set(GNUCXX11_CXX_FLAGS_OPT3   "-g -O3")