Fixes qemu build error.

Since 1.5 qemu defaults to gtk. Since then, the install command triggers
the use of xgettext and msgmerge, both of which are unable to find the
libgettextsrc library without passing LD_LIBRARY_PATH.

source-builder/config/qemu-1-1.cfg

@@ -73,5 +73,6 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
   %{__rmdir} $SB_BUILD_ROOT
 
   cd ${build_dir}
+  %{_ld_library_path}=$SYSROOT/lib \
   %{__make} DESTDIR=$SB_BUILD_ROOT install
   cd ${build_top}