This reverts commit 74d6476a.  Developer
Toolset 7 has apparently not yet been installed on vm139 (the node exclusively
executing this job), see
<https://ci.libreoffice.org/job/lo_callgrind_linux/6525/console>:

> checking for gcc... /opt/rh/devtoolset-7/root/usr/bin/gcc
> checking whether the C compiler works... no
> configure: error: in `/home/buildslave/lode/jenkins/workspace/lo_callgrind_linux':
> configure: error: C compiler cannot create executables
> See `config.log' for more details
> Error running configure at /home/buildslave/lode/jenkins/workspace/lo_callgrind_linux/autogen.sh line 296.