Fix linking warnings due to visibility=hidden being set for the tests.

[Teemperor]

Currently if we compile this test we get ld warning messages like this:

ld: direct access in function ... to global weak symbol. This was likely
caused by different translation units being compiled with different
visibility settings.

This seems to be caused by the fact that visibility=hidden is spreading
from the parent directory to the test directory, even though it should
only land in the src/ directory. As CMAKE_CXX_FLAGS is working on a
per subdirectory basis, we just move the code for handling the source
code to the src/ folder, which should contain the visibility=hidden.

[Teemperor]

Just making a PR to test this on OS X for now.

[phsft-bot]

Starting build on gcc49/centos7, native/mac1012, gcc49/slc6, gcc62/slc6, native/ubuntu14 with flags -Dvc=OFF -Dimt=ON -Dccache=ON
How to customize builds

[Axel-Naumann]

Can you attach the diff -u of the two files? You moving the file and changing it in the same commit makes it impossible for me to figure out what has changed in the content...

[Axel-Naumann]

The diff was personally brought to my office - it's empty. Will merge once Jenkins reports happiness.

[phsft-bot]

Build failed on mac1012/native.
See console output.

Warnings:

• JENKINS-19022: warning: possible memory leak due to Git plugin usage; see: https://wiki.jenkins-ci.org/display/JENKINS/Remove+Git+Plugin+BuildsByBranch+BuildData

Failing tests:

• projectroot.roottest.root.dataframe.roottest_root_dataframe_foreach

[phsft-bot]

Starting build on gcc49/centos7, native/mac1012, gcc49/slc6, gcc62/slc6, native/ubuntu14 with flags -Dvc=OFF -Dimt=ON -Dccache=ON
How to customize builds

[phsft-bot]

Starting build on gcc49/centos7, native/mac1012, gcc49/slc6, gcc62/slc6, native/ubuntu14 with flags -Dvc=OFF -Dimt=ON -Dccache=ON
How to customize builds

[phsft-bot]

Starting build on gcc49/centos7, native/mac1012, gcc49/slc6, gcc62/slc6, native/ubuntu14 with flags -Dvc=OFF -Dimt=ON -Dccache=ON
How to customize builds

[phsft-bot]

Build failed on mac1012/native.
See console output.

Warnings:

• JENKINS-19022: warning: possible memory leak due to Git plugin usage; see: https://wiki.jenkins-ci.org/display/JENKINS/Remove+Git+Plugin+BuildsByBranch+BuildData
• /Volumes/MacintoshHD2/ec/build/workspace/root-pullrequests-build/root/hist/hist/src/TF1.cxx:2693:161: warning: format specifies type 'int' but the argument has type 'size_type' (aka 'unsigned long') [-Wformat]

Failing tests:

• projectroot.roottest.python.JupyROOT.roottest_python_JupyROOT_cppcompleter_doctest

[phsft-bot]

Build failed on ubuntu14/native.
See console output.

Warnings:

• JENKINS-19022: warning: possible memory leak due to Git plugin usage; see: https://wiki.jenkins-ci.org/display/JENKINS/Remove+Git+Plugin+BuildsByBranch+BuildData
• /mnt/vdb/lsf/workspace/root-pullrequests-build/root/hist/hist/src/TF1.cxx:2693:173: warning: format ‘%d’ expects argument of type ‘int’, but argument 5 has type ‘std::vector<double>::size_type {aka long unsigned int}’ [-Wformat=]

Failing tests:

• projectroot.roottest.python.JupyROOT.roottest_python_JupyROOT_cppcompleter_doctest
• projectroot.roottest.root.multicore.roottest_root_multicore_threadExecutor

[phsft-bot]

Build failed on slc6/gcc62.
See console output.

Warnings:

• JENKINS-19022: warning: possible memory leak due to Git plugin usage; see: https://wiki.jenkins-ci.org/display/JENKINS/Remove+Git+Plugin+BuildsByBranch+BuildData
• /mnt/build/jenkins/workspace/root-pullrequests-build/root/hist/hist/src/TF1.cxx:2693:173: warning: format ‘%d’ expects argument of type ‘int’, but argument 5 has type ‘std::vector<double>::size_type {aka long unsigned int}’ [-Wformat=]

Failing tests:

• projectroot.roottest.python.JupyROOT.roottest_python_JupyROOT_cppcompleter_doctest

[phsft-bot]

Build failed on slc6/gcc49.
See console output.

Warnings:

• JENKINS-19022: warning: possible memory leak due to Git plugin usage; see: https://wiki.jenkins-ci.org/display/JENKINS/Remove+Git+Plugin+BuildsByBranch+BuildData
• /mnt/build/jenkins/workspace/root-pullrequests-build/root/hist/hist/src/TF1.cxx:2693:173: warning: format ‘%d’ expects argument of type ‘int’, but argument 5 has type ‘std::vector<double>::size_type {aka long unsigned int}’ [-Wformat=]

Failing tests:

• projectroot.roottest.python.JupyROOT.roottest_python_JupyROOT_cppcompleter_doctest

[Axel-Naumann]

The same failure exists without this PR. Merging!