Add DESTDIR install target

Makefile

@@ -33,7 +33,7 @@ realclean:
 
 install:
 	@echo "Installing"
-	$(TOP)/bin/installmesa
+	$(TOP)/bin/installmesa $(DESTDIR)
 
 # DirectFBGL module installation
 linux-directfb-install:

bin/installmesa

@@ -12,7 +12,7 @@ TOP=.
 INCLUDE_DIR="/usr/local/include"
 LIB_DIR="/usr/local/lib"
 
-
+if [ x$# == "x0" ] ; then
 echo
 echo "***** Mesa installation - You may need root privileges to do this *****"
 echo
@@ -33,7 +33,6 @@ if [ x${INPUT} != "x" ] ; then
 	LIB_DIR=${INPUT}
 fi
 
-
 echo
 echo "About to install Mesa header files (GL/*.h) in: " ${INCLUDE_DIR}/GL
 echo "and Mesa library files (libGL.*, etc) in: " ${LIB_DIR}
@@ -41,6 +40,10 @@ echo "Press <Enter> to continue, or <ctrl>-C to abort."
 
 read INPUT
 
+else
+INCLUDE_DIR=$1/include
+LIB_DIR=$1/lib
+fi
 
 # flags:
 #  -f = force