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)) {
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</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=d756564db5ee46b27ef65d226d16dbb8354e424e'>root</a>/<a href='/guix/log/doc?id=d756564db5ee46b27ef65d226d16dbb8354e424e'>doc</a>/<a href='/guix/log/doc/images?id=d756564db5ee46b27ef65d226d16dbb8354e424e'>images</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/doc/images?id=d756564db5ee46b27ef65d226d16dbb8354e424e&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-05-12 19:27:59 +0200'>2022-05-12</span></td><td><a href='/guix/commit/doc/images?id=eeba993f570483345acd59c2d8709fd5d7ee7ae7'>doc: Add the "Full-source Bootstrap".</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/guix.texi (Reduced Binary Seed Bootstrap): Update and rename to...
(Full-Source Bootstrap): ...this.
* doc/images/gcc-core-mesboot0-graph.dot: Regenerate.
</span></span></td><td>Jan (janneke) Nieuwenhuizen</td></tr>
<tr><td><span title='2020-05-22 16:11:52 +0200'>2020-05-22</span></td><td><a href='/guix/commit/doc/images?id=cd5d5f53228fd5bf96d9f790aa2606ae71fa68d7'>doc: Update 'Bootstrapping' for further binary seed reduction.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/images/gcc-core-mesboot0-graph.dot: New image, replacing
* doc/images/gcc-mesboot0-bag-graph.dot: ... remove file.
* doc/local.mk (DOT_FILES): Update for new image file.
* doc/guix.texi (Reduced Binary Seed Bootstrap): Use it in updated description
of further reduction of the trusted computing base.
</span></span></td><td>Jan Nieuwenhuizen</td></tr>