This patch is an improvement that causes an array object that has a
pragma Linker_Section with a compile-time-known initial value to be
statically initialized in place in the appropriate section.

Tested on x86_64-pc-linux-gnu, committed on trunk

2017-04-25  Bob Duff  <duff@adacore.com>

	* freeze.adb (Freeze_Object_Declaration): Do
	not Remove_Side_Effects if there is a pragma Linker_Section,
	because in that case we want static initialization in the
	appropriate section.