gnu: python-pycrypto: Fix build with Python 3.8.

* gnu/packages/patches/python-pycrypto-time-clock.patch: New file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/python-crypto.scm (python-pycrypto)[source](patches): Add it.

gnu/local.mk

@@ -1387,6 +1387,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/python2-parameterized-docstring-test.patch	\
   %D%/packages/patches/python-paste-remove-timing-test.patch	\
   %D%/packages/patches/python-pycrypto-CVE-2013-7459.patch	\
+  %D%/packages/patches/python-pycrypto-time-clock.patch		\
   %D%/packages/patches/python2-pygobject-2-gi-info-type-error-domain.patch \
   %D%/packages/patches/python-pygpgme-fix-pinentry-tests.patch	\
   %D%/packages/patches/python-robotframework-honor-source-date-epoch.patch \

gnu/packages/patches/python-pycrypto-time-clock.patch

@@ -0,0 +1,23 @@
+Drop use of the deprecated time.clock which was removed in Python 3.8.
+
+Adapted from upstream pull request:
+
+https://github.com/dlitz/pycrypto/pull/296
+
+diff --git a/lib/Crypto/Random/_UserFriendlyRNG.py b/lib/Crypto/Random/_UserFriendlyRNG.py
+--- a/lib/Crypto/Random/_UserFriendlyRNG.py
++++ b/lib/Crypto/Random/_UserFriendlyRNG.py
+@@ -73,8 +73,11 @@ class _EntropyCollector(object):
+         t = time.time()
+         self._time_es.feed(struct.pack("@I", int(2**30 * (t - floor(t)))))
+ 
+-        # Add the fractional part of time.clock()
+-        t = time.clock()
++        # Add the fractional part of time.process_time()
++        try:
++           t = time.process_time()
++        except AttributeError:
++           t = time.clock()
+         self._clock_es.feed(struct.pack("@I", int(2**30 * (t - floor(t)))))
+ 
+ 

gnu/packages/python-crypto.scm

@@ -280,7 +280,8 @@ making them easy to handle and incorporate into other protocols.")
      (origin
       (method url-fetch)
       (uri (pypi-uri "pycrypto" version))
-      (patches (search-patches "python-pycrypto-CVE-2013-7459.patch"))
+      (patches (search-patches "python-pycrypto-CVE-2013-7459.patch"
+                               "python-pycrypto-time-clock.patch"))
       (sha256
        (base32
         "0g0ayql5b9mkjam8hym6zyg6bv77lbh66rv1fyvgqb17kfc1xkpj"))))