[v2] criu: add -fprofile-update=atomic for builds with gcov

Sometimes we see errors like this:
criu/cr-restore.gcda:Merge mismatch for function 106

It proabably means that this gcda file was corrupted. According to the
gcc man page, the -fprofile-update=atomic should fix this problem.

v2: this options appered in gcc7, so we need to install it.

Reported-by: Mr Travis CI
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

.travis.yml

@@ -5,7 +5,7 @@ cache: ccache
 services:
   - docker
 env:
-  - TR_ARCH=local       GCOV=1
+  - TR_ARCH=local
   - TR_ARCH=local       CLANG=1
   - TR_ARCH=alpine
   - TR_ARCH=fedora-asan
@@ -22,6 +22,7 @@ env:
   - TR_ARCH=docker-test
   - TR_ARCH=fedora-rawhide
   - TR_ARCH=fedora-rawhide-aarch64
+  - TR_ARCH=local       GCOV=1
 matrix:
   allow_failures:
     - env: TR_ARCH=docker-test

Makefile

@@ -91,7 +91,7 @@ DEFINES			+= -D_GNU_SOURCE
 
 WARNINGS		:= -Wall -Wformat-security
 
-CFLAGS-GCOV		:= --coverage -fno-exceptions -fno-inline
+CFLAGS-GCOV		:= --coverage -fno-exceptions -fno-inline -fprofile-update=atomic
 export CFLAGS-GCOV
 
 ifneq ($(GCOV),)

scripts/travis/travis-tests

@@ -20,6 +20,13 @@ travis_prep () {
 		CC=clang
 	fi
 
+	[ -n "$GCOV" ] && {
+		apt-add-repository -y "ppa:ubuntu-toolchain-r/test"
+		apt-get update -yq
+		apt-get -yq --no-install-suggests --no-install-recommends --force-yes install g++-7
+		CC=gcc-7
+	}
+
 	# ccache support, only enable for non-GCOV case
 	if [ "$CCACHE" = "1" -a -z "$GCOV" ]; then
 		# ccache is installed by default, need to set it up
@@ -99,7 +106,7 @@ bash ./test/jenkins/criu-inhfd.sh
 
 make -C test/others/mnt-ext-dev/ run
 #make -C test/others/exec/ run
-make -C test/others/make/ run
+make -C test/others/make/ run CC="$CC"
 
 ./test/zdtm.py run -t zdtm/static/env00 --sibling