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)) {
n value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=695db2f98a9099aaea9289f3a34c43e8d120d8b5'>root</a>/<a href='/guix/log/po?id=695db2f98a9099aaea9289f3a34c43e8d120d8b5'>po</a>/<a href='/guix/log/po/doc?id=695db2f98a9099aaea9289f3a34c43e8d120d8b5'>doc</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/po/doc?id=695db2f98a9099aaea9289f3a34c43e8d120d8b5&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2018-11-01 12:36:47 +0100'>2018-11-01</span></td><td><a href='/guix/commit/po/doc?id=1e40e70bfebba47ccea354ddf862276d2c4223ea'>doc: Add German translation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/contributing.de.texi: New file.
* doc/guix.de.texi: New file
* doc/local.mk (TRANSLATED_INFO): Add them.
(info_TEXINFOS): Add guix.de.texi.
* po/doc/guix-manual.de.po: New file.
* po/doc/local.mk (EXTRA_DIST): Add it.
* doc/guix.texi: Document the German translation.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-08-26 12:43:49 +0200'>2018-08-26</span></td><td><a href='/guix/commit/po/doc?id=1d8d69c863ae88d5fc20e52e49a22f68c531c1db'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-08-15 18:54:29 +0200'>2018-08-15</span></td><td><a href='/guix/commit/po/doc?id=524756d127a80beebef04b028fa73b8a99617fe0'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-06-23 16:23:50 +0200'>2018-06-23</span></td><td><a href='/guix/commit/po/doc?id=2cf2c778846153f3d5a56e98232fbef6f71b57a6'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-06-13 18:50:41 +0200'>2018-06-13</span></td><td><a href='/guix/commit/po/doc?id=8c655f31db66a27730cae7c97ba001899143101b'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-06-08 20:38:41 +0200'>2018-06-08</span></td><td><a href='/guix/commit/po/doc?id=7f3f72b292b218873fe3379d5dc5cdae5c4f4747'>nls: Update 'fr' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-06-08 17:04:23 +0200'>2018-06-08</span></td><td><a href='/guix/commit/po/doc?id=dd8646555a979c563e9890dd1189b4d6a4ed4db7'>doc: Update 'fr' translation.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-04-29 21:42:14 +0200'>2018-04-29</span></td><td><a href='/guix/commit/po/doc?id=39764ef893b7b65a8ce55e13746fed8fd0bad6e0'>build: Use only one domain for guix-manual.</a><span class='msg-avail'>...<span class='msg-tooltip'>* Makefile.am (assert-no-store-file-names): Exclude guix-manual.
* po/doc/guix.pot po/doc/contributing.pot: Merge into...
* po/doc/guix-manual.pot: ...this.
* po/doc/guix.fr.po po/doc/contributing.fr.po: Merge into...
* po/doc/guix-manual.fr.po: ...this.
* doc/local.mk: Replace old file names.
* po/doc/local.mk: Replace old file names.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-04-19 21:32:07 +0200'>2018-04-19</span></td><td><a href='/guix/commit/po/doc?id=bf5c74e713c623cbb0001eb36af6998e92243482'>gnu: doc: Add French documentation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/contributing.fr.texi: New file.
* doc/guix.fr.texi: New file.
* doc/local.mk (TRANSLATED_INFO): Add them.
(info_TEXINFOS): Add guix.fr.texi.
* po/doc/contributing.fr.po: New file.
* po/doc/guix.fr.po: New file.
* po/doc/local.mk (EXTRA_DIST): Add them.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2018-04-19 21:30:30 +0200'>2018-04-19</span></td><td><a href='/guix/commit/po/doc?id=b9fe8fd662180e64156d2b95a671242c20f0acfc'>gnu: doc: Allow documentation to be translated.</a><span class='msg-avail'>...<span class='msg-tooltip'>* po/doc/contributing.pot: New file.
* po/doc/guix.pot: New file.
* po/doc/local.mk: New file.
* Makefile.am: Include it. Add gettext command. Add silent rules for po4a.
* configure.ac: Look for po4a-translate and po4a-updatepo.
* doc/local.mk: Add rules to generate translated texi files.
(TRANSLATED_INFO): New variable.
(BUILT_SOURCES, EXTRA_DIST, MAINTAINERCLEANFILES): Add it.
* .gitignore: Add generated files.
</span></span></td><td>Julien Lepiller</td></tr>