cmake: drop "-march=native" from CXX_FLAGS (#1429)

this breaks the cross-compiling, and we can not assume that the building
machine and the target machine share the same CPU spec.

Signed-off-by: Kefu Chai <kchai@redhat.com>

CMakeLists.txt

@@ -91,7 +91,7 @@ else()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -W -Wextra -Wall -Werror")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-compare -Wshadow -Wno-unused-parameter -Wno-unused-variable -Woverloaded-virtual -Wnon-virtual-dtor -Wno-missing-field-initializers")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native -fno-omit-frame-pointer -momit-leaf-frame-pointer")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-omit-frame-pointer -momit-leaf-frame-pointer")
 endif()
 
 option(WITH_ASAN "build with ASAN" OFF)