Index: /issm/trunk-jpl/m4/issm_options.m4
===================================================================
--- /issm/trunk-jpl/m4/issm_options.m4	(revision 15528)
+++ /issm/trunk-jpl/m4/issm_options.m4	(revision 15529)
@@ -624,9 +624,9 @@
 
 	 PETSCINCL=" -I$PETSC_ROOT/include"
-	 dnl Add other location (maybe not needed anymore)
-	 if test -d "$PETSC_ROOT/$PETSC_ARCH/include"; then
+	 dnl Add other location (not needed anymore since at least PETSc 3.0)
+	 if test "x$PETSC_ARCH" != "x" && test -d "$PETSC_ROOT/$PETSC_ARCH/include"; then
 	  PETSCINCL+=" $PETSC_ROOT/$PETSC_ARCH/include"
 	 fi
-	 if test -d "$PETSC_ROOT/include/$PETSC_ARCH"; then
+	 if test "x$PETSC_ARCH" != "x" && test -d "$PETSC_ROOT/include/$PETSC_ARCH"; then
 	  PETSCINCL+=" $PETSC_ROOT/include/$PETSC_ARCH"
 	 fi