Don't let the buildsystem mess with optimization and debug flags and set stuff
like -march=native which is not generic (and is very arch specific).

--- CMakeLists.txt
+++ CMakeLists.txt
@@ -22,17 +22,13 @@ endif()
 set(PROJECT_VERSION ${vis_version})
 project(${PROJECT_NAME} VERSION ${vis_version} LANGUAGES CXX C)
 
-if(NOT DEFINED VIS_COMPILER_ARCH)
-    set(VIS_COMPILER_ARCH "native")
-endif()
-
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-omit-frame-pointer -D__extern_always_inline=inline -D_XOPEN_SOURCE_EXTENDED")
-set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -ggdb -g3 -ffast-math -march=x86-64 -mtune=generic -DVIS_LOG_DEBUG")
-set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -ffast-math -g1 -O3 -march=${VIS_COMPILER_ARCH} -fno-omit-frame-pointer -DNDEBUG")
+set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -ggdb -g3 -ffast-math -DVIS_LOG_DEBUG")
+set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -ffast-math -fno-omit-frame-pointer -DNDEBUG")
 
 set(CMAKE_LD_FLAGS "${CMAKE_LD_FLAGS} ${VIS_DEFAULT_FLAGS} -fno-omit-frame-pointer -D__extern_always_inline=inline -D_XOPEN_SOURCE_EXTENDED")
-set(CMAKE_LD_FLAGS_DEBUG "${CMAKE_LD_FLAGS_DEBUG} -ggdb -g3 -ffast-math -march=x86-64 -mtune=generic -DVIS_LOG_DEBUG")
-set(CMAKE_LD_FLAGS_RELEASE "${CMAKE_LD_FLAGS_RELEASE} -ffast-math -g1 -O3 -march=${VIS_COMPILER_ARCH} -fno-omit-frame-pointer -DNDEBUG")
+set(CMAKE_LD_FLAGS_DEBUG "${CMAKE_LD_FLAGS_DEBUG} -ggdb -g3 -ffast-math -DVIS_LOG_DEBUG")
+set(CMAKE_LD_FLAGS_RELEASE "${CMAKE_LD_FLAGS_RELEASE} -ffast-math -fno-omit-frame-pointer -DNDEBUG")
 
 if(DEFINED VIS_SANITIZER)
     # compile with O1 to cause a little more havoc