--- makefile.orig	2017-12-18 03:43:13 UTC
+++ makefile
@@ -277,7 +277,7 @@ reconfigure:
 	@${PYTHON} ${PETSC_ARCH}/lib/petsc/conf/reconfigure-${PETSC_ARCH}.py
 #
 install:
-	@${PYTHON} ./config/install.py -destDir=${DESTDIR}
+	@${PYTHON} ./config/install.py -destDir=${DESTDIR}${PREFIX}
 	${OMAKE} PETSC_ARCH=${PETSC_ARCH} PETSC_DIR=${PETSC_DIR} mpi4py-install petsc4py-install
 
 newall:
