Re: back x11 configure tests

[Fred Kiefer]

Am 13.03.2011 22:27, schrieb Eric Wasylishen:
> Hi,
> I was getting a missing symbol error when I tried to drag and drop. It turns 
> out that back wasn't linked to libXext; the configure test AC_CHECK_LIB(Xext, 
> main) was failing (silently). This is on Ubuntu 10.10.
>
> I changed it to: (and did the same for Xt and Xmu)
>
>    AC_CHECK_LIB(Xext, main)
>    if test "$HAVE_LIBXext" = no; then
>      PKG_CHECK_MODULES([XEXT], [xext])
>    fi
>
> so it uses pkg-config if the AC_CHECK_LIB can't find the library. This fixed 
> the problem for me, but I'm not sure if it's the right thing to do.
>
> One thing is that according to the autoconf docs, PKG_CHECK_MODULES will cause 
> a hard failure if it can't find the library. Are Xext, Xt, and Xmu hard 
> dependencies of x11 back?


Shouldn't we use the values that PKG_CHECK_MODULES set in XXX_LIBS and 
XXX_CFLAGS. Otherwise, if these get set to non-default values the test 
will state that the libraries are present, but compilation will fail 
later on.

I am really not sure which of these extensions are strict requirements 
for GNUstep to build. Most likely we could change our code to work 
without them as well. In XGServerWindow.m we use XShapeCombineMask in 
context.c we use XmuLookupStandardColormap. We also use XShmQueryVersion 
but these are already protected with checks.

I would be surprised to learn that we actually use Xt, no idea why we 
are checking for it.