Submitted upstream at https://gitlab.kitware.com/cmake/cmake/-/merge_requests/7670.

diff --git a/Source/cmCurl.cxx b/Source/cmCurl.cxx
index 28ee24dfe9..fc5405213a 100644
--- a/Source/cmCurl.cxx
+++ b/Source/cmCurl.cxx
@@ -38,6 +38,14 @@ std::string cmCurlSetCAInfo(::CURL* curl, const std::string& cafile)
     ::CURLcode res = ::curl_easy_setopt(curl, CURLOPT_CAINFO, cafile.c_str());
     check_curl_result(res, "Unable to set TLS/SSL Verify CAINFO: ");
   }
+  /* Honor the user-configurable OpenSSL environment variables. */
+  else if (cmSystemTools::GetEnv("SSL_CERT_FILE", e)) {
+    ::CURLcode res = ::curl_easy_setopt(curl, CURLOPT_CAINFO, e.c_str());
+    check_curl_result(res, "Unable to set TLS/SSL Verify CAINFO: ");
+  } else if (cmSystemTools::GetEnv("SSL_CERT_DIR", e)) {
+    ::CURLcode res = ::curl_easy_setopt(curl, CURLOPT_CAPATH, e.c_str());
+    check_curl_result(res, "Unable to set TLS/SSL Verify CAINFO: ");
+  }
 #ifdef CMAKE_FIND_CAFILE
 #  define CMAKE_CAFILE_FEDORA "/etc/pki/tls/certs/ca-bundle.crt"
   else if (cmSystemTools::FileExists(CMAKE_CAFILE_FEDORA, true)) {
/refs/?id=1c194cd2bb5191f73499ec869952859d711ff225'>refs</a><a class='active' href='/guix/log/gnu/installer/substitutes.scm'>log</a><a href='/guix/tree/gnu/installer/substitutes.scm?id=1c194cd2bb5191f73499ec869952859d711ff225'>tree</a><a href='/guix/commit/gnu/installer/substitutes.scm?id=1c194cd2bb5191f73499ec869952859d711ff225'>commit</a><a href='/guix/diff/gnu/installer/substitutes.scm?id=1c194cd2bb5191f73499ec869952859d711ff225'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/installer/substitutes.scm'>
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<div class='path'>path: <a href='/guix/log/?id=1c194cd2bb5191f73499ec869952859d711ff225'>root</a>/<a href='/guix/log/gnu?id=1c194cd2bb5191f73499ec869952859d711ff225'>gnu</a>/<a href='/guix/log/gnu/installer?id=1c194cd2bb5191f73499ec869952859d711ff225'>installer</a>/<a href='/guix/log/gnu/installer/substitutes.scm?id=1c194cd2bb5191f73499ec869952859d711ff225'>substitutes.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/installer/substitutes.scm?id=1c194cd2bb5191f73499ec869952859d711ff225&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-12-11 21:37:07 +0100'>2020-12-11</span></td><td><a href='/guix/commit/gnu/installer/substitutes.scm?id=8361817bf693742757b096468198626f297bb09e'>install: Discover local substitute servers.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/installer/substitutes.scm: New file.
* gnu/installer/newt/substitutes.scm: New file.
* gnu/local.mk (INSTALLER_MODULES): Add them.
* po/guix/POTFILES.in: Add gnu/installer/newt/substitutes.scm.
* gnu/installer/proxy.scm (with-silent-shepherd): Move to ...
* gnu/installer/utils.scm: ... here.
* gnu/installer/record.scm (&lt;installer&gt;)[substitutes-page]: New field.
* gnu/installer/newt.scm (substitutes-page): New procedure,
(newt-installer): register it.
* gnu/installer.scm (installer-steps): Add "substitutes-page" step.
* gnu/system/install.scm (%installation-services): Add avahi-service-type and
enable substitute server discover in guix-service-type.
[&lt;name-service-switch&gt;]: Set it to %mdns-host-lookup-nss.
</span></span></td><td>Mathieu Othacehe</td></tr>