--- lwan.orig/CMakeLists.txt	2016-06-22 21:20:56.423255000 +0200
+++ lwan.patched/CMakeLists.txt	2016-06-22 21:22:11.323256834 +0200
@@ -64,11 +64,13 @@
 	endif()
 endif()
 
-if (CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
+include(CheckCCompilerFlag)
+
+check_c_compiler_flag(-mtune=native HAS_MTUNE_NATIVE)
+if (HAS_MTUNE_NATIVE)
 	set(C_FLAGS_REL "-mtune=native")
 endif()
 
-include(CheckCCompilerFlag)
 if (APPLE)
 	check_c_compiler_flag(-Wl,-bind_at_load HAS_IMMEDIATE_BINDING)
 	if (HAS_IMMEDIATE_BINDING)