libpayload: Make sure to install into the right DESTDIR

A recent update broke installation of commonlib headers with a relative
path in $(DESTDIR), which is the default. Make sure to install into the
right location in case we changed the current directory.

Change-Id: I61fa4aa0ecd0f81ee03ff89183e1b65e7875dea6
Signed-off-by: Nico Huber <nico.h@gmx.de>
Fixes: ee53dfd07d3b (libpayload: Remove shell for loops in install Makefile target)
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79908
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/payloads/libpayload/Makefile.inc b/payloads/libpayload/Makefile.inc
index e4d45a6..61f932f 100644
--- a/payloads/libpayload/Makefile.inc
+++ b/payloads/libpayload/Makefile.inc
@@ -128,8 +128,8 @@
 	install -m 755 -d $(DESTDIR)/libpayload/include
 	find include -type d -exec install -m755 -d $(DESTDIR)/libpayload/{} \;
 	find include -type f -exec install -m644 {} $(DESTDIR)/libpayload/{} \;
-	cd $(coreboottop)/src/commonlib/bsd && find include -type d -exec install -m755 -d $(DESTDIR)/libpayload/{} \;
-	cd $(coreboottop)/src/commonlib/bsd && find include -type f -exec install -m644 {} $(DESTDIR)/libpayload/{} \;
+	cd $(coreboottop)/src/commonlib/bsd && find include -type d -exec install -m755 -d $(abspath $(DESTDIR))/libpayload/{} \;
+	cd $(coreboottop)/src/commonlib/bsd && find include -type f -exec install -m644 {} $(abspath $(DESTDIR))/libpayload/{} \;
 	install -m 644 $(obj)/libpayload-config.h $(DESTDIR)/libpayload/include
 	$(foreach item,$(includes), \
 		install -m 755 -d $(DESTDIR)/libpayload/include/$(call extract_nth,2,$(item)); \