Core: Remove the MersenneTwiser-library (SFMT is now considered stable enough for full deployment)

cmake/compiler/gcc/settings.cmake

@@ -3,14 +3,12 @@ add_definitions(-D_BUILD_DIRECTIVE='"${CMAKE_BUILD_TYPE}"')
 
 add_definitions(-fno-delete-null-pointer-checks)
 
-if( USE_SFMT)
-  if(PLATFORM EQUAL 32)
-    # Required on 32-bit systems to enable SSE2 (standard on x64)
-    add_definitions(-msse2 -mfpmath=sse)
-  endif()
-  add_definitions(-DHAVE_SSE2 -D__SSE2__)
-  message(STATUS "GCC: SFMT enabled, SSE2 flags forced")
+if(PLATFORM EQUAL 32)
+  # Required on 32-bit systems to enable SSE2 (standard on x64)
+  add_definitions(-msse2 -mfpmath=sse)
 endif()
+add_definitions(-DHAVE_SSE2 -D__SSE2__)
+message(STATUS "GCC: SSE2 flags forced")
 
 if( WITH_WARNINGS )
   add_definitions(-Wall -Wfatal-errors -Wextra)