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=38b46a3e32c6827bc7255a9027c9e77d3becdff0'>root</a>/<a href='/guix/log/tests?id=38b46a3e32c6827bc7255a9027c9e77d3becdff0'>tests</a>/<a href='/guix/log/tests/networking.scm?id=38b46a3e32c6827bc7255a9027c9e77d3becdff0'>networking.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/tests/networking.scm?id=38b46a3e32c6827bc7255a9027c9e77d3becdff0&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-10-30 18:15:54 -0400'>2019-10-30</span></td><td><a href='/guix/commit/tests/networking.scm?id=97bc3cbea5fc281a299c03eaaa3be5baf21ea673'>services: ntp: Ensure no double quotes are output to config file.</a><span class='msg-avail'>...</span></td><td>Maxim Cournoyer</td></tr>