Install docs to non-generic name

Closes: #1073800

debian/clean

 gen_data
 results/
+q3c.md

debian/patches/non-generic-docname.patch

+From 44a34187ab3ecd1a49b818a7d61f707e666007c7 Mon Sep 17 00:00:00 2001
+From: Christoph Berg <myon@debian.org>
+Date: Wed, 19 Jun 2024 14:50:39 +0200
+Subject: [PATCH] Install docs to non-generic name
+
+Previously, README.md was installed to .../doc/extension/README.md which
+conflicts with other extensions doing the same mistake. Fix by adding a
+symlink q3c.md and using that in DOCS. Keep the original README.md name
+to please GitHub.
+
+Debian Bug: https://bugs.debian.org/1073800
+
+diff --git a/Makefile b/Makefile
+index 11b3ab2..fbbd1bb 100644
+--- a/Makefile
++++ b/Makefile
+@@ -3,7 +3,7 @@ EXTVERSION := $(shell grep default_version $(EXTENSION).control | \
+ 		 sed -e "s/default_version[[:space:]]*=[[:space:]]*'\([^']*\)'/\1/")
+ 
+ 
+-DOCS = README.md
++DOCS = q3c.md
+ OBJS = dump.o q3c.o q3c_poly.o q3cube.o
+ MODULE_big = q3c
+ DATA = $(wildcard scripts/*sql)

debian/patches/series

 ldflags
 skip-slow-tests
+non-generic-docname.patch

debian/rules

@@ -5,3 +5,7 @@ override_dh_pgxs_test:
 
 %:
 	dh $@ --with pgxs_loop
+
+override_dh_auto_install:
+	cp README.md q3c.md
+	dh_auto_install