Remove CURL warning and Makefile fix (#5110)

* Makefile: bash is required for LICENSES.txt
* Conditionally use the older or the newer CURLOPT

CURLOPT_PROTOCOLS_STR is available since CURL 7.85.0

Author: emasab

Makefile

@@ -9,6 +9,7 @@ DOC_FILES+=	LICENSE LICENSES.txt INTRODUCTION.md README.md \
 
 PKGNAME?=	librdkafka
 VERSION?=	$(shell python3 packaging/get_version.py src/rdkafka.h)
+SHELL	=	bash
 
 # Jenkins CI integration
 BUILD_NUMBER ?= 1

src/rdhttp.c

@@ -139,8 +139,15 @@ rd_http_error_t *rd_http_req_init(rd_http_req_t *hreq, const char *url) {
         hreq->hreq_buf = rd_buf_new(1, 1024);
 
         curl_easy_setopt(hreq->hreq_curl, CURLOPT_URL, url);
+#if CURL_AT_LEAST_VERSION(7, 85, 0)
+        curl_easy_setopt(hreq->hreq_curl, CURLOPT_PROTOCOLS_STR, "http,https");
+#else
+        /* As of 06/10/2025 Debian 10 and CentOS Stream 9 ship with
+         * older CURL versions, remove this condition once they're not supported
+         * anymore. */
         curl_easy_setopt(hreq->hreq_curl, CURLOPT_PROTOCOLS,
                          CURLPROTO_HTTP | CURLPROTO_HTTPS);
+#endif
         curl_easy_setopt(hreq->hreq_curl, CURLOPT_MAXREDIRS, 16);
         curl_easy_setopt(hreq->hreq_curl, CURLOPT_TIMEOUT, 30);
         curl_easy_setopt(hreq->hreq_curl, CURLOPT_ERRORBUFFER,