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
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