build: start playing with PGO

CMakeLists.txt

@@ -57,14 +57,15 @@ function(configure_compiler_target target)
   if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
     target_compile_options(${target} PRIVATE
       $<$<AND:$<CONFIG:Debug>,$<COMPILE_LANGUAGE:C,CXX>>:-O0 -Wall>
-      $<$<AND:$<CONFIG:Release>,$<COMPILE_LANGUAGE:C,CXX>>:-O2 -w -flto>
+      $<$<AND:$<CONFIG:Release>,$<COMPILE_LANGUAGE:C,CXX>>:-O2 -w -flto -fprofile-generate>
     )
     target_link_options(${target} PRIVATE
-      $<$<CONFIG:Release>:-flto>
+      $<$<CONFIG:Release>:-flto -fprofile-generate>
     )
   endif()
 endfunction()
 
+link_directories("${CMAKE_CURRENT_SOURCE_DIR}/linux-includes/")
 
 # ---
 # Configuration