Make sure the build system honors C_INCLUDE_PATH and LIBRARY_PATH when
looking for headers and libraries.

--- Python-2.7.10/setup.py	2015-10-07 18:33:18.125153186 +0200
+++ Python-2.7.10/setup.py	2015-10-07 18:33:47.497347552 +0200
@@ -526,6 +526,14 @@ class PyBuildExt(build_ext):
             inc_dirs += ['/system/include', '/atheos/autolnk/include']
             inc_dirs += os.getenv('C_INCLUDE_PATH', '').split(os.pathsep)
 
+        # Always honor these variables.
+        if not cross_compiling:
+            lib_dirs += os.getenv('LIBRARY_PATH', '').split(os.pathsep)
+            inc_dirs += os.getenv('C_INCLUDE_PATH', '').split(os.pathsep)
+        else:
+            lib_dirs = os.getenv('CROSS_LIBRARY_PATH', '').split(os.pathsep)
+            inc_dirs = os.getenv('CROSS_CPATH', '').split(os.pathsep)
+
         # OSF/1 and Unixware have some stuff in /usr/ccs/lib (like -ldb)
         if host_platform in ['osf1', 'unixware7', 'openunix8']:
             lib_dirs += ['/usr/ccs/lib']
s'><tr><td>
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<div class='path'>path: <a href='/guix/log/?id=2fca4acdf6942ce9fbaf3580dda4e5fa7cabd2f2'>root</a>/<a href='/guix/log/po?id=2fca4acdf6942ce9fbaf3580dda4e5fa7cabd2f2'>po</a>/<a href='/guix/log/po/packages?id=2fca4acdf6942ce9fbaf3580dda4e5fa7cabd2f2'>packages</a>/<a href='/guix/log/po/packages/sk.po?id=2fca4acdf6942ce9fbaf3580dda4e5fa7cabd2f2'>sk.po</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/packages/sk.po?id=2fca4acdf6942ce9fbaf3580dda4e5fa7cabd2f2&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-05-10 22:34:43 -0400'>2021-05-10</span></td><td><a href='/guix/commit/po/packages/sk.po?id=21fcced608c93e1ac836cdd9ab8c5d200c667e75'>nls: Update translations.</a></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2021-04-18 13:18:13 +0200'>2021-04-18</span></td><td><a href='/guix/commit/po/packages/sk.po?id=77c6c0aa577939da4d35a1ba95ea998459a3f337'>nls: Add Slovak translation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* po/packages/sk.po: New file.
* po/packages/LINGUAS: Add 'sk'.
* po/doc/guix-manual.sk.po: New file.
* doc/local.mk (info_TEXINFOS): Add it.
* po/doc/local.mk (DOC_PO_FILES): Add it.
</span></span></td><td>Julien Lepiller</td></tr>