tests: add callgrind start/stop macros in benchmark programs

Change-Id: Ibd875f4275431ebcbeba2fffe319956580714553
Refs: #3610
diff --git a/wscript b/wscript
index 9f3a0cb..b029c75 100644
--- a/wscript
+++ b/wscript
@@ -109,6 +109,7 @@
       Logs.warn('Dropping privileges is not supported on this platform')
 
     conf.check_cxx(header_name='ifaddrs.h', mandatory=False)
+    conf.check_cxx(header_name='valgrind/valgrind.h', define_name='HAVE_VALGRIND', mandatory=False)
 
     boost_libs = 'system chrono program_options random thread log log_setup'
     if conf.options.with_tests: