bundle-library: Add optional Makefile target

make bundle-library can be used by third party developers that want to
statically link against duckdb library to generate a single static library
comprised of all statically built extensions and all necessary third party
libraries

Solves (to some degree) duckdb#9475 and issue
encountered in the go-duckdb API while bundling extensions

Makefile

@@ -427,3 +427,13 @@ generate-files:
 	python3 scripts/generate_functions.py
 	python3 scripts/generate_serialization.py
 	python3 scripts/generate_enum_util.py
+
+bundle-library: release
+	cd build/release && \
+	mkdir -p bundle && \
+	cp src/libduckdb_static.a bundle/. && \
+	cp third_party/*/libduckdb_*.a bundle/. && \
+	cp extension/*/lib*_extension.a bundle/. && \
+	cd bundle && \
+	find . -name '*.a' -exec ${AR} -x {} \; && \
+	${AR} cr ../libduckdb_bundle.a *.o