Pass on DESTDIR

================================================================================
--- Makefile.in
+++ Makefile.in
@@ -53,6 +53,8 @@
 manext      = 1
 localedir   = $(prefix)/share/locale
 
+DESTDIR = 
+
 CC = @CC@
 CFLAGS = @CFLAGS@
 CPPFLAGS = @CPPFLAGS@
@@ -79,7 +81,8 @@
 MAKEDEFS = CC='$(CC)' CPPFLAGS='$(CPPFLAGS)' DEFS='$(DEFS)' \
 CFLAGS='$(CFLAGS)' LDFLAGS='$(LDFLAGS)' LIBS='$(LIBS)' \
 prefix='$(prefix)' exec_prefix='$(exec_prefix)' bindir='$(bindir)' \
-infodir='$(infodir)' mandir='$(mandir)' manext='$(manext)'
+infodir='$(infodir)' mandir='$(mandir)' manext='$(manext)' \
+DESTDIR='$(DESTDIR)'
 
 # subdirectories in the distribution
 SUBDIRS = src doc po util windows