By default commands such as "ctest" would not look for certificates
at all: <https://issues.guix.gnu.org/issue/37371>.

This changes CMake such that commands honor SSL_CERT_FILE and SSL_CERT_DIR
as well as /etc/ssl/certs.

--- cmake-3.13.1/Source/cmCurl.cxx	2019-09-10 17:27:36.926907260 +0200
+++ cmake-3.13.1/Source/cmCurl.cxx	2019-09-10 17:52:35.475903919 +0200
@@ -2,11 +2,8 @@
    file Copyright.txt or https://cmake.org/licensing for details.  */
 #include "cmCurl.h"
 
-#if !defined(CMAKE_USE_SYSTEM_CURL) && !defined(_WIN32) &&                    \
-  !defined(__APPLE__) && !defined(CURL_CA_BUNDLE) && !defined(CURL_CA_PATH)
 #  define CMAKE_FIND_CAFILE
 #  include "cmSystemTools.h"
-#endif
 #include "cmStringAlgorithms.h"
 
 // curl versions before 7.21.5 did not provide this error code
@@ -30,6 +27,19 @@
     ::CURLcode res = ::curl_easy_setopt(curl, CURLOPT_CAINFO, cafile);
     check_curl_result(res, "Unable to set TLS/SSL Verify CAINFO: ");
   }
+
+  /* Honor the usual 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)) {
02b8bf76106436a31ac54a340a09'/><select name='qt'>
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</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=341ac566c2bc02b8bf76106436a31ac54a340a09'>root</a>/<a href='/guix/log/tests?id=341ac566c2bc02b8bf76106436a31ac54a340a09'>tests</a>/<a href='/guix/log/tests/pack.scm?id=341ac566c2bc02b8bf76106436a31ac54a340a09'>pack.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/tests/pack.scm?id=341ac566c2bc02b8bf76106436a31ac54a340a09&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-07-18 02:02:34 -0400'>2021-07-18</span></td><td><a href='/guix/commit/tests/pack.scm?id=aeded14b8342c1e72afd014a1bc121770f8c3a1c'>pack: Allow embedding custom control files in deb packs.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2021-06-29 14:53:21 -0400'>2021-06-29</span></td><td><a href='/guix/commit/tests/pack.scm?id=82daab42811a2e3c7684ebdf12af75ff0fa67b99'>pack: Add support for the deb format.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2021-06-29 14:53:21 -0400'>2021-06-29</span></td><td><a href='/guix/commit/tests/pack.scm?id=8108c266dc2fbc70602b2aa5c6887bf17bed16e8'>tests: pack: Fix compressor extension.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2020-07-20 23:25:09 +0200'>2020-07-20</span></td><td><a href='/guix/commit/tests/pack.scm?id=b3802495f607fd5e17c5acf0be2ee014036e2464'>pack: Build the store database under a UTF-8 locale.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-07-20 23:25:09 +0200'>2020-07-20</span></td><td><a href='/guix/commit/tests/pack.scm?id=181e0dddd68dc58190bd4831ea5d1ecbd420d83a'>pack: 'self-contained-tarball' runs derivation in a UTF-8local.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-12-26 12:29:44 +0100'>2019-12-26</span></td><td><a href='/guix/commit/tests/pack.scm?id=3c45b53ec9025f4b95ec003ff99caa3e6fe506ab'>gnu: Remove squashfs-tools-next.</a><span class='msg-avail'>...</span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2019-08-27 12:20:44 +0200'>2019-08-27</span></td><td><a href='/guix/commit/tests/pack.scm?id=7979a287f8eb84cbbfa44629951572408939a756'>pack: Create /tmp in Docker images.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>