From: vagrant@reproducible-builds.org
Subject: Use relative symlinks when linking to headers.
Date: Fri, May 7 18:33:50 2021 +0900

Using the absolute build path only works during the build; the
symlinks are included in the tarball, which results in broken symlinks
in the tarball included in the bluez-source package.

diff --git a/Makefile.am b/Makefile.am
index 8bca5acfa..b2eafcb5f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -790,7 +790,7 @@ $(lib_libbluetooth_la_OBJECTS): $(local_headers)
 
 lib/bluetooth/%.h: lib/%.h
 	$(AM_V_at)$(MKDIR_P) lib/bluetooth
-	$(AM_V_GEN)$(LN_S) -f $(abspath $<) $@
+	$(AM_V_GEN)$(LN_S) -f ../$(shell basename $@) $@
 
 ell/shared: Makefile
 	$(AM_V_at)$(MKDIR_P) ell