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
s customized Guix</td><td class='sub right'></td></tr></table>
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<div class='path'>path: <a href='/guix/log/?id=e81e154c40b262b1c7a0928cbc712e3631f6342a'>root</a>/<a href='/guix/log/gnu?id=e81e154c40b262b1c7a0928cbc712e3631f6342a'>gnu</a>/<a href='/guix/log/gnu/packages?id=e81e154c40b262b1c7a0928cbc712e3631f6342a'>packages</a>/<a href='/guix/log/gnu/packages/regex.scm?id=e81e154c40b262b1c7a0928cbc712e3631f6342a'>regex.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/packages/regex.scm?id=e81e154c40b262b1c7a0928cbc712e3631f6342a&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2018-01-02 17:30:17 +0100'>2018-01-02</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=1c848029b7b24beb0d4dcb4eff46b7fb2787c29e'>gnu: re2: Update to 2018-01-01.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2017-12-07 17:36:16 +0100'>2017-12-07</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=61bfc18ee8fa084133a6dac500c0f8f037e5d925'>gnu: re2: Update to 2017-12-01.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2017-11-04 00:07:39 +0100'>2017-11-04</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=d94c67925479939b505f37fb454514a52626ef4e'>gnu: re2: Update to 2017-11-01.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2017-09-20 20:58:04 -0400'>2017-09-20</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=dc1d3cdef70f0e3c047c229c2a0e561d1f47bde8'>gnu: Use 'modify-phases' syntax.</a><span class='msg-avail'>...</span></td><td>Kei Kebreau</td></tr>
<tr><td><span title='2017-08-01 23:37:20 +0200'>2017-08-01</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=fc8f0631b4163d31a97fccb9a14201b5e861fa52'>gnu: re2: Update to 2017-08-01.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2017-07-04 02:52:25 +0200'>2017-07-04</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=92d7e87c5922bac7746f201f2ccb028cc5e7aaee'>gnu: re2: Update to 2017-07-01.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2017-06-03 00:28:18 +0200'>2017-06-03</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=84a8ec13a6e836e982943be0cedd581b93ef0b73'>gnu: re2: Update to 2017-06-01.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2017-05-09 20:52:29 +0200'>2017-05-09</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=f8ff364ab77a92951b54eedb0c985f5b498206e0'>gnu: re2: Update to 2017-05-01.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2017-05-07 17:35:07 +0200'>2017-05-07</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=7a4a64e99e65e96a4dc3e65ae691b4c80b7642e8'>gnu: re2: Add missing '#:modules' imports.</a><span class='msg-avail'>...</span></td><td>Sergei Trofimovich</td></tr>
<tr><td><span title='2017-04-06 15:07:55 +0200'>2017-04-06</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=2aa78c8f04660fbbca9fc57ecee19788ee6f4e32'>gnu: re2: Update to 2017-04-01.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2017-03-11 22:23:28 +0100'>2017-03-11</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=612af7ff66e0d5018bb696ff0140805bc8b5194e'>gnu: re2: Set CXX for cross-compilation.</a><span class='msg-avail'>...</span></td><td>Sergei Trofimovich</td></tr>
<tr><td><span title='2017-03-01 20:41:41 +0100'>2017-03-01</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=8c58c53beba33beefd657f466d2ba758f2096a08'>gnu: re2: Update to 2017-03-01.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2017-01-30 14:55:10 +0100'>2017-01-30</span></td><td><a href='/guix/commit/gnu/packages/regex.scm?id=4a9c4a55acd2554e39d91fb2a0f87f9107f28194'>gnu: re2: Update to 2017-01-01.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>