process_ctrl_c_stub: forward exit code of the child process
process_ctrl_c_stub: forward exit code of the child process

If the child process cannot be started, return -1.

Task-number: QTCREATORBUG-6458
Change-Id: I0392d883773f3037ac29dccc4d4a3c330efde838
Reviewed-by: Oswald Buddenhagen <6a8868beda3e139b5ac22b2534a23d3e6ba81819@nokia.com>
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@nokia.com>

Distrotech/qtcreator,richardmg/qtcreator,martyone/sailfish-qtcreator,KDE/android-qt-creator,danimo/qt-creator,amyvmiwei/qt-creator,martyone/sailfish-qtcreator,omniacreator/qtcreator,malikcjm/qtcreator,malikcjm/qtcreator,danimo/qt-creator,danimo/qt-creator,hdweiss/qt-creator-visualizer,KDE/android-qt-creator,martyone/sailfish-qtcreator,malikcjm/qtcreator,kuba1/qtcreator,azat/qtcreator,ostash/qt-creator-i18n-uk,xianian/qt-creator,KDE/android-qt-creator,omniacreator/qtcreator,martyone/sailfish-qtcreator,duythanhphan/qt-creator,maui-packages/qt-creator,farseerri/git_code,azat/qtcreator,KDAB/KDAB-Creator,KDE/android-qt-creator,kuba1/qtcreator,Distrotech/qtcreator,duythanhphan/qt-creator,malikcjm/qtcreator,darksylinc/qt-creator,richardmg/qtcreator,KDAB/KDAB-Creator,amyvmiwei/qt-creator,richardmg/qtcreator,jonnor/qt-creator,syntheticpp/qt-creator,farseerri/git_code,jonnor/qt-creator,xianian/qt-creator,farseerri/git_code,kuba1/qtcreator,ostash/qt-creator-i18n-uk,maui-packages/qt-creator,duythanhphan/qt-creator,xianian/qt-creator,maui-packages/qt-creator,azat/qtcreator,AltarBeastiful/qt-creator,farseerri/git_code,ostash/qt-creator-i18n-uk,colede/qtcreator,bakaiadam/collaborative_qt_creator,xianian/qt-creator,ostash/qt-creator-i18n-uk,colede/qtcreator,KDE/android-qt-creator,hdweiss/qt-creator-visualizer,colede/qtcreator,kuba1/qtcreator,martyone/sailfish-qtcreator,syntheticpp/qt-creator,ostash/qt-creator-i18n-uk,KDE/android-qt-creator,darksylinc/qt-creator,darksylinc/qt-creator,amyvmiwei/qt-creator,amyvmiwei/qt-creator,KDAB/KDAB-Creator,kuba1/qtcreator,duythanhphan/qt-creator,xianian/qt-creator,syntheticpp/qt-creator,AltarBeastiful/qt-creator,darksylinc/qt-creator,AltarBeastiful/qt-creator,amyvmiwei/qt-creator,farseerri/git_code,Distrotech/qtcreator,amyvmiwei/qt-creator,farseerri/git_code,azat/qtcreator,maui-packages/qt-creator,bakaiadam/collaborative_qt_creator,duythanhphan/qt-creator,xianian/qt-creator,richardmg/qtcreator,malikcjm/qtcreator,maui-packages/qt-creator,KDAB/KDAB-Creator,KDE/android-qt-creator,amyvmiwei/qt-creator,xianian/qt-creator,syntheticpp/qt-creator,ostash/qt-creator-i18n-uk,colede/qtcreator,hdweiss/qt-creator-visualizer,KDAB/KDAB-Creator,syntheticpp/qt-creator,danimo/qt-creator,farseerri/git_code,Distrotech/qtcreator,martyone/sailfish-qtcreator,kuba1/qtcreator,Distrotech/qtcreator,AltarBeastiful/qt-creator,omniacreator/qtcreator,omniacreator/qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,KDAB/KDAB-Creator,hdweiss/qt-creator-visualizer,bakaiadam/collaborative_qt_creator,azat/qtcreator,xianian/qt-creator,darksylinc/qt-creator,danimo/qt-creator,Distrotech/qtcreator,kuba1/qtcreator,danimo/qt-creator,darksylinc/qt-creator,farseerri/git_code,jonnor/qt-creator,hdweiss/qt-creator-visualizer,danimo/qt-creator,hdweiss/qt-creator-visualizer,bakaiadam/collaborative_qt_creator,colede/qtcreator,kuba1/qtcreator,richardmg/qtcreator,AltarBeastiful/qt-creator,omniacreator/qtcreator,duythanhphan/qt-creator,darksylinc/qt-creator,danimo/qt-creator,Distrotech/qtcreator,danimo/qt-creator,richardmg/qtcreator,martyone/sailfish-qtcreator,bakaiadam/collaborative_qt_creator,omniacreator/qtcreator,omniacreator/qtcreator,AltarBeastiful/qt-creator,KDE/android-qt-creator,AltarBeastiful/qt-creator,ostash/qt-creator-i18n-uk,colede/qtcreator,jonnor/qt-creator,colede/qtcreator,amyvmiwei/qt-creator,bakaiadam/collaborative_qt_creator,martyone/sailfish-qtcreator,malikcjm/qtcreator,duythanhphan/qt-creator,jonnor/qt-creator,bakaiadam/collaborative_qt_creator,maui-packages/qt-creator,syntheticpp/qt-creator,maui-packages/qt-creator,syntheticpp/qt-creator,kuba1/qtcreator,AltarBeastiful/qt-creator,darksylinc/qt-creator,azat/qtcreator,jonnor/qt-creator,malikcjm/qtcreator,richardmg/qtcreator