Add all /gnu/store/ prefixes found in PYTHONPATH to the prefixes where
site-packages (and .pth files) are searched.

*** Python-2.7.11/Lib/site.py.orig	2016-10-17 23:27:23.746149690 +0200
--- Python-2.7.11/Lib/site.py	2016-10-17 23:44:51.930871644 +0200
***************
*** 65,70 ****
--- 65,82 ----
  
  # Prefixes for site-packages; add additional prefixes like /usr/local here
  PREFIXES = [sys.prefix, sys.exec_prefix]
+ # Guix: Add all /gnu/store-paths in PYTHONPATH--these are all
+ # "prefixes".  This is required to search .pth files in all python
+ # packages contained in /gnu/store which is required to make
+ # .pth-defined namespace packages work.
+ # This is necessary if the packages are not merged into a single
+ # `site-packages` directory (like when using `guix environment`) but
+ # listed in PYTHONPATH (like when running `guix build`).
+ for p in sys.path:
+     if p.startswith('/gnu/store/'):
+         PREFIXES.append(p[:p.find('/', 44)]) # find first pathsep after hash
+ del p
+ 
  # Enable per user site-packages directory
  # set it to False to disable the feature or True to force the feature
  ENABLE_USER_SITE = None
434c'>refs</a><a class='active' href='/guix/log/gnu/build/linux-initrd.scm'>log</a><a href='/guix/tree/gnu/build/linux-initrd.scm?id=14a50b62d4e8765b794861226d79f6872d6c434c'>tree</a><a href='/guix/commit/gnu/build/linux-initrd.scm?id=14a50b62d4e8765b794861226d79f6872d6c434c'>commit</a><a href='/guix/diff/gnu/build/linux-initrd.scm?id=14a50b62d4e8765b794861226d79f6872d6c434c'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/build/linux-initrd.scm'>
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<div class='path'>path: <a href='/guix/log/?id=14a50b62d4e8765b794861226d79f6872d6c434c'>root</a>/<a href='/guix/log/gnu?id=14a50b62d4e8765b794861226d79f6872d6c434c'>gnu</a>/<a href='/guix/log/gnu/build?id=14a50b62d4e8765b794861226d79f6872d6c434c'>build</a>/<a href='/guix/log/gnu/build/linux-initrd.scm?id=14a50b62d4e8765b794861226d79f6872d6c434c'>linux-initrd.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/build/linux-initrd.scm?id=14a50b62d4e8765b794861226d79f6872d6c434c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-12-15 17:32:10 +0100'>2020-12-15</span></td><td><a href='/guix/commit/gnu/build/linux-initrd.scm?id=6a060ff27ff68384d7c90076baa36c349fff689d'>store-copy: 'populate-store' can optionally deduplicate files.</a><span class='msg-avail'>...<span class='msg-tooltip'>Until now deduplication was performed as an additional pass after
copying files, which involve re-traversing all the files that had just
been copied.

* guix/store/deduplication.scm (copy-file/deduplicate): New procedure.
* tests/store-deduplication.scm ("copy-file/deduplicate"): New test.
* guix/build/store-copy.scm (populate-store): Add #:deduplicate?
parameter and honor it.
* tests/gexp.scm ("gexp-&gt;derivation, store copy"): Pass #:deduplicate? #f
to 'populate-store'.
* gnu/build/image.scm (initialize-root-partition): Pass #:deduplicate?
to 'populate-store'.  Pass #:deduplicate? #f to 'register-closure'.
* gnu/build/vm.scm (root-partition-initializer): Likewise.
* gnu/build/install.scm (populate-single-profile-directory): Pass
 #:deduplicate? #f to 'populate-store'.
* gnu/build/linux-initrd.scm (build-initrd): Likewise.
* guix/scripts/pack.scm (self-contained-tarball)[import-module?]: New
procedure.
[build]: Pass it as an argument to 'source-module-closure'.
* guix/scripts/pack.scm (squashfs-image)[build]: Wrap in
'with-extensions'.
* gnu/system/linux-initrd.scm (expression-&gt;initrd)[import-module?]: New
procedure.
[builder]: Pass it to 'source-module-closure'.
* gnu/system/install.scm (cow-store-service-type)[import-module?]: New
procedure.  Pass it to 'source-module-closure'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-11-21 12:39:14 +0100'>2020-11-21</span></td><td><a href='/guix/commit/gnu/build/linux-initrd.scm?id=2200bb214690ebc78b9fa42887ac9dfb8035bd4f'>linux-initrd: Remove unnecessary timestamp reset phase.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/build/linux-initrd.scm (write-cpio-archive): Mention timestamps in
docstring.
(build-initrd): Remove unnecessary timestamp reset phase.
</span></span></td><td>Ludovic Courtès</td></tr>