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)) {
nu/packages/protobuf.scm'>
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<div class='path'>path: <a href='/guix/log/?id=ad64b09df4bcf0a57753c9ad2cdd442b78e205d3'>root</a>/<a href='/guix/log/gnu?id=ad64b09df4bcf0a57753c9ad2cdd442b78e205d3'>gnu</a>/<a href='/guix/log/gnu/packages?id=ad64b09df4bcf0a57753c9ad2cdd442b78e205d3'>packages</a>/<a href='/guix/log/gnu/packages/protobuf.scm?id=ad64b09df4bcf0a57753c9ad2cdd442b78e205d3'>protobuf.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/packages/protobuf.scm?id=ad64b09df4bcf0a57753c9ad2cdd442b78e205d3&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-02-10 20:18:05 +0100'>2020-02-10</span></td><td><a href='/guix/commit/gnu/packages/protobuf.scm?id=307feca4e62aad13b7c5c019d9568790f96ba0b9'>gnu: python-protobuf: Update to 3.11.3.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-02-10 20:18:04 +0100'>2020-02-10</span></td><td><a href='/guix/commit/gnu/packages/protobuf.scm?id=1d5261dacc31103836eab6d607a028fda0f6bc1d'>gnu: protobuf: Update to 3.11.3.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-01-03 13:54:11 +0100'>2020-01-03</span></td><td><a href='/guix/commit/gnu/packages/protobuf.scm?id=599d0190607f73772cdcf26c3a7563b6a837c69b'>gnu: protozero: Update to 1.6.8.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-11-19 13:11:16 +0900'>2019-11-19</span></td><td><a href='/guix/commit/gnu/packages/protobuf.scm?id=63edbb65e4d16ebbd4c3977e93c3ebcbf0495c46'>gnu: emacs-protobuf-mode: Rename the set-emacs-load-path phase.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2019-11-12 20:09:50 +0100'>2019-11-12</span></td><td><a href='/guix/commit/gnu/packages/protobuf.scm?id=b506b98e75e579c5e50abd84e4745e688242449c'>gnu: protobuf: Update to 3.10.1.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-10-21 00:26:14 +0200'>2019-10-21</span></td><td><a href='/guix/commit/gnu/packages/protobuf.scm?id=7373eb8304e0ebbfabe66deb59e78187013403dd'>gnu: protobuf: Update to 3.10.0.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2019-10-21 00:26:14 +0200'>2019-10-21</span></td><td><a href='/guix/commit/gnu/packages/protobuf.scm?id=bd1213708cb4d10b3a9bb633a2b21dc82f39f98b'>gnu: protobuf-c: Update to 1.3.2.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>