detect-toolchains: detect also compilers in the path on osx
detect-toolchains: detect also compilers in the path on osx

Change-Id: Ifd0762775adbb36c7952f1773e7de14c79f919d1
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@digia.com>

qtproject/qt-labs-qbs,gatzka/qt-labs-qbs,gatzka/qt-labs-qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,Distrotech/qbs,Distrotech/qbs,gatzka/qt-labs-qbs,qt-labs/qbs,gatzka/qt-labs-qbs,qt-labs/qbs,qt-labs/qbs,villytiger/qbs,qt-labs/qbs,villytiger/qbs,qtproject/qt-labs-qbs,Distrotech/qbs,qtproject/qt-labs-qbs,gatzka/qt-labs-qbs,gatzka/qt-labs-qbs,villytiger/qbs,villytiger/qbs,Distrotech/qbs,villytiger/qbs,Distrotech/qbs,qt-labs/qbs,Distrotech/qbs,qtproject/qt-labs-qbs,qt-labs/qbs,Distrotech/qbs,qt-labs/qbs,villytiger/qbs,qtproject/qt-labs-qbs,gatzka/qt-labs-qbs