I just tried the following in gst-plugins-bad:

--8<---------------cut here---------------start------------->8---

     (build-system gnu-build-system)
+    (native-search-paths
+     ;; Note: This search path is respected by the `curl` command-line tool only.
+     ;; Ideally we would bake this into libcurl itself so other users can benefit,
+     ;; but it's not supported upstream due to thread safety concerns.
+     (list (search-path-specification
+            (variable "CURLOPT_CAPATH")
+            (files '("etc/ssl/certs")))
+           (search-path-specification
+            (variable "CURLOPT_CAINFO")
+            (files '("etc/ssl/certs/ca-certificates.crt")))))
     (arguments
      '(#:tests? #f ; XXX: 13 of 53 tests fail
--8<---------------cut here---------------end--------------->8---

Didn't work :/

Gotta try harder...

-- 
Pierre Neidhardt
https://ambrevar.xyz/