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

--- a/setup.py	2015-10-07 23:32:58.891329173 +0200
+++ b/setup.py	2015-10-07 23:46:29.653349924 +0200
@@ -676,15 +676,15 @@
         # if a file is found in one of those directories, it can
         # be assumed that no additional -I,-L directives are needed.
         if not CROSS_COMPILING:
-            self.lib_dirs = self.compiler.library_dirs + system_lib_dirs
-            self.inc_dirs = self.compiler.include_dirs + system_include_dirs
+            self.lib_dirs = os.getenv('LIBRARY_PATH', '').split(os.pathsep)
+            self.inc_dirs = os.getenv('C_INCLUDE_PATH', '').split(os.pathsep)
         else:
             # Add the sysroot paths. 'sysroot' is a compiler option used to
             # set the logical path of the standard system headers and
             # libraries.
-            self.lib_dirs = (self.compiler.library_dirs +
+            self.lib_dirs = (os.getenv('CROSS_LIBRARY_PATH', '').split(os.pathsep) +
                              sysroot_paths(('LDFLAGS', 'CC'), system_lib_dirs))
-            self.inc_dirs = (self.compiler.include_dirs +
+            self.inc_dirs = (os.getenv('CROSS_C_INCLUDE_PATH', '').split(os.pathsep) +
                              sysroot_paths(('CPPFLAGS', 'CFLAGS', 'CC'),
                                            system_include_dirs))
 
6f8'>commit</a><a href='/guix/diff/gnu/installer/steps.scm?id=786eb92c0f1ea8a22c9cf160440cd0722052e6f8'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/installer/steps.scm'>
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<div class='path'>path: <a href='/guix/log/?id=786eb92c0f1ea8a22c9cf160440cd0722052e6f8'>root</a>/<a href='/guix/log/gnu?id=786eb92c0f1ea8a22c9cf160440cd0722052e6f8'>gnu</a>/<a href='/guix/log/gnu/installer?id=786eb92c0f1ea8a22c9cf160440cd0722052e6f8'>installer</a>/<a href='/guix/log/gnu/installer/steps.scm?id=786eb92c0f1ea8a22c9cf160440cd0722052e6f8'>steps.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/installer/steps.scm?id=786eb92c0f1ea8a22c9cf160440cd0722052e6f8&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-11-02 15:52:19 +0100'>2022-11-02</span></td><td><a href='/guix/commit/gnu/installer/steps.scm?id=62a3756bd90c922c701e899a6c01c556d8e3c75a'>installer: Skip the backtrace page on user abort.</a><span class='msg-avail'>...<span class='msg-tooltip'>When the user aborts the installation because a core dump is discovered or the
installation command failed, displaying the abort backtrace doesn't make much
sense. Hide it when the abort condition is &amp;user-abort-error and skip directly
to the dump page.

* gnu/installer/steps.scm (&amp;user-abort-error): New variable.
(user-abort-error?): New procedure.
* gnu/installer/newt/final.scm (run-install-failed-page): Raise a
user-abort-error.
* gnu/installer/newt/welcome.scm (run-welcome-page): Ditto.
* gnu/installer.scm (installer-program): Hide the backtrace page and directly
propose to dump the report when the a &amp;user-abort-error is raised.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2022-08-08 11:54:25 +0200'>2022-08-08</span></td><td><a href='/guix/commit/gnu/installer/steps.scm?id=ff9522fb69b9f4a31a5b766029e26dc53a2d1cf8'>installer: Add comments and vertical space to the generated config.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/installer/parted.scm (user-partitions-&gt;configuration): Introduce
vertical space and a comment.
* gnu/installer/services.scm (G_): New macro.
(%system-services): Add comment for OpenSSH.
(system-services-&gt;configuration): Add vertical space and comments.
* gnu/installer/user.scm (users-&gt;configuration): Add comment.
* gnu/installer/steps.scm (format-configuration): Add comment.
(configuration-&gt;file): Expound leading comment.  Pass #:format-comment
to 'pretty-print-with-comments/splice'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-08-08 11:54:24 +0200'>2022-08-08</span></td><td><a href='/guix/commit/gnu/installer/steps.scm?id=cd1a98b928be9602ebf103744164ace7bfcae22c'>installer: Render the final configuration with (guix read-print).</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/installer.scm (module-to-import?): Return #t for (guix read-print).
* gnu/installer/steps.scm (configuration-&gt;file): Use
'pretty-print-with-comments/splice' instead of 'for-each' and 'pretty-print'.
</span></span></td><td>Ludovic Courtès</td></tr>