build: add -flto flag for performance and perf configuration

configure

@@ -20,6 +20,9 @@ for arg in $@; do
 	--coverage)
 	    coverage="yes"
 	;;
+	--perf)
+	    perf="yes"
+	;;
 	*)
 	    echo "unknown option $arg"
 	    exit 1
@@ -62,8 +65,13 @@ if [[ "$coverage" == "yes" ]]; then
    ldflags_extra="$ldflags_extra -lgcov --coverage"
 fi
 
+release_cflags="-O3 -flto"
 if [[ "$release" == "yes" ]]; then
-    ccflags_extra="$ccflags_extra -O3"
+    ccflags_extra="$ccflags_extra $release_cflags"
+fi
+
+if [[ "$perf" == "yes" ]]; then
+    ccflags_extra="$ccflags_extra $release_cflags -ggdb"
 fi
 
 add_define CCFLAGS_EXTRA "$ccflags_extra"