Don't persist LDFLAGS into package database.

https://bugs.gentoo.org/609624
--- a/X11.buildinfo.in
+++ b/X11.buildinfo.in
@@ -5,3 +5,3 @@ buildable: @BUILD_PACKAGE_BOOL@
 cc-options: @X_CFLAGS@ @CPPFLAGS@
-ld-options: @X_LIBS@ @LDFLAGS@
+ld-options: @X_LIBS@
 extra-libraries: @EXTRA_LIBRARIES@