Makefile: add an option to opt out of libbrotli

Makefile

@@ -19,7 +19,15 @@ GOLANGCI_LINT_VERSION ?= "v1.37.0"
 REDIS_VERSION ?= "5.0.8"
 TOOLS_MOD_DIR := ./internal/tools
 
-BUILD_TAGS:=brotli
+BUILD_TAGS:=
+
+# the original Makefile had brotli alwas included
+# for this historical reason:
+#  - brotli is an *opt-out* feature (included by default, use NO_LIBBROTLI to *not* include it),
+#  - the other libs are opt-in features (not included by default, use USE_LIBSODIUM or USE_LZO to include them)
+ifndef NO_LIBBROTLI
+	BUILD_TAGS:=brotli
+endif
 
 ifdef USE_LIBSODIUM
 	BUILD_TAGS:=$(BUILD_TAGS) libsodium
@@ -233,7 +241,8 @@ install:
 	@echo "Nothing to be done. Use pg_install/mysql_install/mongo_install/fdb_install/gp_install... instead."
 
 link_brotli:
-	./link_brotli.sh
+	@if [ -z "${NO_LIBBROTLI}" ]; then ./link_brotli.sh; fi
+	@if [ -n "${NO_LIBBROTLI}" ]; then echo "info: NO_LIBBROTLI is set, skipping link_brotli job"; fi
 
 link_libsodium:
 	@if [ ! -z "${USE_LIBSODIUM}" ]; then\
@@ -242,7 +251,7 @@ link_libsodium:
 
 unlink_brotli:
 	rm -rf vendor/github.com/google/brotli/*
-	mv tmp/brotli/* vendor/github.com/google/brotli/
+	if [ -z "${NO_LIBBROTLI}" ]; then mv tmp/brotli/* vendor/github.com/google/brotli/; fi
 	rm -rf tmp/brotli
 
 unlink_libsodium: