Configure doesn't fail when Xrender.h is missing

From build-dev, Omair Majid wrote:

So this one turns out to be a bug in how we use AC_CHECK_HEADERS. If I
remove the package that provides this header file on my machine,
configure tells me that the header is missing but does not indicate an
error:

checking for IceConnectionNumber in -lICE... yes
checking for X11/extensions/shape.h... yes
checking for X11/extensions/Xrender.h... no
checking for X11/extensions/XTest.h... yes
checking cups/cups.h usability... yes
checking cups/cups.h presence... yes

The documentation for AC_CHECK_HEADERS [1] states:

"""
If action-if-found is given, it is additional shell code to execute when
one of the header files is found
"""

So what happens is that as long as the last header in the list
[X11/extensions/shape.h X11/extensions/Xrender.h X11/extensions/XTest.h]
is found, X11_A_OK is set to "yes", and the build continues.

A one-line fix is:
http://cr.openjdk.java.net/~omajid/webrevs/x11-header-check/00/