Purity: don't look for library dependencies (of the form `-lfoo') in
/lib and /usr/lib.  Likewise, when searching for included Makefiles,
don't look in /usr/include and friends.

Borrowed from similar patch for GNU Make and adjusted for Remake.

--- remake-4.3+dbg-1.5/src/read.c.orig	2020-03-14 17:06:16.000000000 -0500
+++ remake-4.3+dbg-1.5/src/read.c	2020-07-31 22:34:03.862383862 -0500
@@ -104,7 +104,7 @@
 # define INCLUDEDIR "."
 #endif
     INCLUDEDIR,
-#ifndef _AMIGA
+#if 0
     "/usr/gnu/include",
     "/usr/local/include",
     "/usr/include",
--- remake-4.3+dbg-1.5/src/remake.c.orig	2020-03-14 17:06:16.000000000 -0500
+++ remake-4.3+dbg-1.5/src/remake.c	2020-07-31 22:34:26.798330508 -0500
@@ -1665,8 +1665,10 @@
 {
   static const char *dirs[] =
     {
+#if 0
       "/lib",
       "/usr/lib",
+#endif
 #if defined(WINDOWS32) && !defined(LIBDIR)
 /*
  * This is completely up to the user at product install time. Just define
ht'></td></tr></table>
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<div class='path'>path: <a href='/guix/log/?id=21656ffa3b6d78a610f0befced20cc9b4b3baab6'>root</a>/<a href='/guix/log/m4?id=21656ffa3b6d78a610f0befced20cc9b4b3baab6'>m4</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/m4?id=21656ffa3b6d78a610f0befced20cc9b4b3baab6&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-02-22 00:45:58 +0100'>2020-02-22</span></td><td><a href='/guix/commit/m4?id=378918725259d221222dd0b1831fbaa3e0a17e1f'>build: Depend on guile-ssh 0.12.0</a><span class='msg-avail'>...</span></td><td>Lars-Dominik Braun</td></tr>
<tr><td><span title='2019-08-17 19:26:21 +0200'>2019-08-17</span></td><td><a href='/guix/commit/m4?id=611a64bd7e0893057cd04dcdc2a8d5e7ecc39e45'>build: 'GUIX_CHECK_GUILE_JSON' really checks for Guile-JSON 3.x.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-07-25 00:16:41 +0200'>2019-07-25</span></td><td><a href='/guix/commit/m4?id=81c3dc32244a17241d74eea9fa265edfcb326f6d'>maint: Switch to Guile-JSON 3.x.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-05-06 23:21:33 +0200'>2019-05-06</span></td><td><a href='/guix/commit/m4?id=fea338c6ca1922097fa233be85f424c152a4f507'>Add (guix lzlib).</a><span class='msg-avail'>...</span></td><td>Pierre Neidhardt</td></tr>
<tr><td><span title='2018-11-23 15:42:00 +0100'>2018-11-23</span></td><td><a href='/guix/commit/m4?id=60e1c1099fc3d73ed7d3235e71aae5d00ab7d773'>Update Guile-SQLite3 URL everywhere.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-09-04 17:25:11 +0200'>2018-09-04</span></td><td><a href='/guix/commit/m4?id=ca719424455465fca4b872c371daf2a46de88b33'>Switch to Guile-Gcrypt.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-06-01 15:35:15 +0200'>2018-06-01</span></td><td><a href='/guix/commit/m4?id=d59e75f3b5b82692bd250a1a3a9965397bb588c5'>build: Check for Guile-SQLite3.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-02-26 18:19:34 +0100'>2018-02-26</span></td><td><a href='/guix/commit/m4?id=1d84d7bf6052c0c80bd212d4524876576e9817d4'>build: Require Guile &gt;= 2.0.13.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-01-06 14:45:01 +0100'>2018-01-06</span></td><td><a href='/guix/commit/m4?id=142182514b84ee233bc27e574df2ca2074291525'>build: Detect broken 'equal?' in Guile 2.2.1.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-06-30 00:16:50 +0200'>2017-06-30</span></td><td><a href='/guix/commit/m4?id=1d97fd8cb60f0b5f386f834940f859ff0b0bcc71'>build: Remove check for broken (srfi srfi-37).</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-02-20 12:58:07 +0200'>2017-02-20</span></td><td><a href='/guix/commit/m4?id=3b88f3767d9f3ad2cc64173525cd53d429bfe7e7'>gnu: Add bootstrap-binaries for 'aarch64-linux'.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2016-11-25 23:44:20 +0100'>2016-11-25</span></td><td><a href='/guix/commit/m4?id=21531add3205e400707c8fbfd841845f9a71863a'>offload: Use Guile-SSH instead of GNU lsh.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2016-08-10 15:40:22 -0400'>2016-08-10</span></td><td><a href='/guix/commit/m4?id=4ed40a3e6ca030573ded52233bd9e72dcdb85697'>build: Correctly determine the system type for GNU/Hurd systems.</a><span class='msg-avail'>...</span></td><td>Manolis Ragkousis</td></tr>
<tr><td><span title='2016-07-20 11:42:17 +0200'>2016-07-20</span></td><td><a href='/guix/commit/m4?id=7575655212ecfbcd1f04e429c8a7a41f8720d027'>Merge branch 'master' into core-updates</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2016-07-19 00:07:12 +0200'>2016-07-19</span></td><td><a href='/guix/commit/m4?id=721539026dda02e58addbb618f2102b31a2927f8'>Add (guix zlib).</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>