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))
 
b7aafae28573354181426f460cdeb4'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/nix/libutil'>
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<div class='path'>path: <a href='/guix/log/?id=8c1c045a87b7aafae28573354181426f460cdeb4'>root</a>/<a href='/guix/log/nix?id=8c1c045a87b7aafae28573354181426f460cdeb4'>nix</a>/<a href='/guix/log/nix/libutil?id=8c1c045a87b7aafae28573354181426f460cdeb4'>libutil</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/nix/libutil?id=8c1c045a87b7aafae28573354181426f460cdeb4&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-01-09 17:40:54 +0100'>2023-01-09</span></td><td><a href='/guix/commit/nix/libutil?id=407175a1d0e29f45639e7f28a531b3981cd20085'>daemon: Improve error message for wrong hash sizes.</a><span class='msg-avail'>...<span class='msg-tooltip'>* nix/libutil/hash.cc (parseHash): Show the hash algorithm name and
expected size in the error message.
* tests/derivations.scm ("fixed-output derivation, invalid hash size"):
New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-12-18 01:16:47 +0100'>2022-12-18</span></td><td><a href='/guix/commit/nix/libutil?id=2d4d26769d6a3be1b21302b0bb2bd099fd55ccf8'>daemon: Make "opening file" error messages distinguishable.</a><span class='msg-avail'>...<span class='msg-tooltip'>* nix/libstore/build.cc (DerivationGoal::openLogFile): Customize
"opening file" error message.
* nix/libutil/hash.cc (hashFile): Likewise.
* nix/libutil/util.cc (readFile, writeFile): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-11-19 23:04:19 +0100'>2021-11-19</span></td><td><a href='/guix/commit/nix/libutil?id=24224530d1f4a70808d003ba8dce849b77625b79'>daemon: Micro-optimize 'deletePath'.</a><span class='msg-avail'>...<span class='msg-tooltip'>'remove' calls 'unlink' first and falls back to 'rmdir' upon EISDIR.
This change gets rid of the 'unlink' call for every directory being
removed.

* nix/libutil/util.cc (_deletePath): Call 'unlink' or 'rmdir' depending
on 'st.st_mode', rather than call 'remove'.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-12-08 22:30:07 +0100'>2020-12-08</span></td><td><a href='/guix/commit/nix/libutil?id=2e308238ad09e9527f9b8c3ec4a90b6b05a93367'>daemon: 'Agent' constructor takes a list of environment variables.</a><span class='msg-avail'>...<span class='msg-tooltip'>* nix/libutil/util.hh (struct Agent)[Agent]: Add 'env' parameter.
* nix/libutil/util.cc (Agent::Agent): Honor it.
</span></span></td><td>Ludovic Courtès</td></tr>