libaio: Backport DESTDIR patch to simplify the Makefile

Fixes issue where OpenWrt CFLAGS like relro were not being passed.

Updated license information.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

libs/libaio/patches/005_destdir.patch

@@ -0,0 +1,34 @@
+From 4059161333a14a0c705efecc5765b6cb2a29ae02 Mon Sep 17 00:00:00 2001
+From: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
+Date: Oct 22 2018 18:43:14 +0000
+Subject: Makefile: add missing DESTDIR variable use
+
+
+Patch borrowed from OpenEmbedded, available at
+recipes/libaio/libaio-0.3.106/destdir.patch in their source tree.
+
+It just adds support for the traditional DESTDIR variable to install
+the library in a different sysroot than the normal /.
+
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
+[JEM: I couldn't verify the initial author of this change, but it's
+ trivial.  For information on the DESTDIR convention, see:
+ https://www.gnu.org/prep/standards/html_node/DESTDIR.html]
+Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
+
+---
+
+diff --git a/Makefile b/Makefile
+index e9dbdb0..c1fb831 100644
+--- a/Makefile
++++ b/Makefile
+@@ -14,7 +14,7 @@ all:
+ 	@$(MAKE) -C src
+ 
+ install:
+-	@$(MAKE) -C src install prefix=$(prefix) includedir=$(includedir) libdir=$(libdir)
++	@$(MAKE) -C src install prefix=$(DESTDIR)$(prefix) includedir=$(DESTDIR)$(includedir) libdir=$(DESTDIR)$(libdir)
+ 
+ check:
+ 	@$(MAKE) -C harness check
+