--- xvi-2.50.3/Makefile	Wed Jun  7 04:02:54 2017
+++ xvi-2.50.3-p/Makefile	Thu Dec  5 12:56:15 2019
@@ -6,7 +6,7 @@
 #
 #	Martin Guy, 8 April 2006
 
-INSTALLROOT=/usr
+INSTALLROOT=${prefix}
 
 BINDIR=$(DESTDIR)$(INSTALLROOT)/bin
 HELPDIR=$(DESTDIR)$(INSTALLROOT)/share/xvi
@@ -16,7 +16,7 @@
 INSTALL?=install
 MAKE?=make
 
-OPTFLAG = -O2
+OPTFLAG = -O2 -I${prefix}/include
 
 # Default target for "make"
 all:
@@ -31,7 +31,8 @@
 
 install: all
 	$(INSTALL) -d $(BINDIR) $(HELPDIR) $(MANDIR) $(DOCDIR)
-	$(INSTALL) -m 755 -s src/xvi $(BINDIR)
+	cp src/xvi $(BINDIR)
+	chmod 755 $(BINDIR)/xvi
 	$(INSTALL) -m 644 src/xvi.help $(HELPDIR)
 	$(INSTALL) -m 644 doc/xvi.1 $(MANDIR)