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']
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<div class='path'>path: <a href='/guix/log/?id=e3fe8eed8f254ab1778e1c6db9bcdade30551de2'>root</a>/<a href='/guix/log/etc?id=e3fe8eed8f254ab1778e1c6db9bcdade30551de2'>etc</a>/<a href='/guix/log/etc/init.d?id=e3fe8eed8f254ab1778e1c6db9bcdade30551de2'>init.d</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/etc/init.d?id=e3fe8eed8f254ab1778e1c6db9bcdade30551de2&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-07-07 23:54:20 -0400'>2021-07-07</span></td><td><a href='/guix/commit/etc/init.d?id=4cbe0127a668cbcc64087c5d311308b59d39b104'>guix-install.sh: Prompt for configuring substitutes discovery.</a><span class='msg-avail'>...<span class='msg-tooltip'>Also ensure prompt_yes_no always print the message with a trailing space,
which is more pleasing to the eye.

* etc/guix-daemon.conf.in &lt;--discover=no&gt;: New guix-daemon option.
* etc/guix-daemon.service.in: Likewise.
* etc/init.d/guix-daemon.in: Likewise.
* etc/openrc/guix-daemon.in: Likewise.
* etc/guix-install.sh (configure_substitute_discovery): New procedure.
(sys_enable_guix_daemon): Ask the user whether automatic substitute discovery
should be enabled.  Set the '--discover' argument accordingly.
(prompt_yes_no): Add a trailing space to the message.
(sys_authorize_build_farms): Remove trailing space from the message argument.
* NEWS (Distribution): Add news.
</span></span></td><td>Maxim Cournoyer</td></tr>