support ROOTDEBUG environment variable, its value is used to set gDebug at startup and overrides the value in a rootrc file. Convenient to quickly turn on debug mode in TROOT startup.
support ROOTDEBUG environment variable, its value is used to set gDebug
at startup and overrides the value in a rootrc file. Convenient to quickly
turn on debug mode in TROOT startup.


git-svn-id: ecbadac9c76e8cf640a0bca86f6bd796c98521e3@7462 27541ba8-7e3a-0410-8455-c3a389f83636

bbannier/ROOT,dawehner/root,bbannier/ROOT,bbannier/ROOT,dawehner/root,bbannier/ROOT,bbannier/ROOT,dawehner/root,dawehner/root,dawehner/root,dawehner/root,bbannier/ROOT,dawehner/root,dawehner/root,bbannier/ROOT