Philippe fixed a typo in Makefile.win32gcc.

The -pthread switch also needs to be removed when linking. Instead of
introducing another if clause in configure I filtered it out in
wingcc_ld.sh. De we need REENTRANT here as well?

configure checks for the X libs, but not for the X headers. At least for
cygwin it has happened several times now that people ran into problems
with that: configure completes successfully, even though only X11 libs
were installed, but no headers. This patch adds a check
for X11/Xlib.h, and tells people to install X11-devel if not found.


git-svn-id: http://root.cern.ch/svn/root/trunk@9350 27541ba8-7e3a-0410-8455-c3a389f83636