RFC xorg: fix installation paths (branch yem/xorg)

Hi Peter.
That's wrong, double-sysroot is natively removed by the newer versions of pkgconf, if you have this:

./usr/lib/pkgconfig/libxslt.pc:Libs: -L${libdir} -lxslt -lxml2 -L/home/gustavoz/b/midx11/output/host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib -lz -lm -ldl -lm

And do this:

$ ./pkg-config --libs libxslt
-L/home/gustavoz/b/midx11/output/host/usr/x86_64-buildroot-linux-gnu/sysroot/usr/lib 
-lxslt  -lz -ldl -lm -lxml2

The output is as expected.

The problem is two-fold as we discussed with Yann last night. On one side the pkg-config manpage says:

PKG_CONFIG_SYSROOT_DIR
Modify -I and -L to use the directories located in target sys? root. this option is useful when cross-compiling packages that use pkg-config to determine CFLAGS and LDFLAGS. -I and -L are modified to point to the new system root. this means that a -I/usr/include/libfoo will become -I/var/target/usr/include/lib? foo with a PKG_CONFIG_SYSROOT_DIR equal to /var/target (same rule apply to -L)

So pkgconf is being "too happy" in applying the sysroot prefix to all directories it finds in any variable.

On the other hand on the previous 0001-fix-variable.patch it did:

if ( !strcmp(req.variable, "includedir") ||
         !strcmp(req.variable, "mapdir") ||
         !strcmp(req.variable, "sdkdir") ||
         !strcmp(req.variable, "libdir"))
               printf("%s%s\n", sysroot_dir, req.buf);
       else
               printf("%s\n", req.buf);

So it was adding the sysroot prefix for mapdir & sdkdir as well, very much out of specification (we'll call the manpage a spec), catering for package abuse.

In the end our previous pkgconf was working out of spec, which may be ok, but poses the question, how many of these variables should be patched/prefixed as well? Because in the future other packages with their $nonstandard variable may need this as well, and patching and patching pkgconf for eternity doesn't sound so great.

First pkgconf should be patched to fix the out-of-spec functionality and send that upstream, but variable exceptions won't roll.

For the second problem i think mangling the .pc files would be best for the special variables, based on a per-package definition where you can say which other variables should be prefixed.

Regards.