Log Message:
devel/glib2: Fix build failure on Darwin

The new patch sets LD_LIBRARY_PATH so that uninstalled
glib-compile-resources can find libraries. This fixes the following
error during build:

[651/1015] Generating plugin-resources.c with a custom command.
FAILED: gio/tests/plugin-resources.c
/Users/pbulk/pkgsrc/work/devel/glib2/work/glib-2.62.4/output/gio/glib-compile-resources \ 
--target=gio/tests/plugin-resources.c \ 
--sourcedir=/Users/pbulk/pkgsrc/work/devel/glib2/work/glib-2.62.4/gio/tests \ 
--generate-source --c-name _g_plugin ../gio/tests/test4.gresource.xml
dyld: Library not loaded: @rpath/libgio-2.0.0.dylib
  Referenced from: \ 
/Users/pbulk/pkgsrc/work/devel/glib2/work/glib-2.62.4/output/gio/glib-compile-re \ 
sources
  Reason: image not found