Update example/linalg/example_solve_custom.f90

Co-authored-by: Jeremie Vandenplas <jeremie.vandenplas@gmail.com>

Author: jalvesz

example/linalg/example_solve_custom.f90

@@ -132,8 +132,8 @@ program example_solve_custom
     x = 0._dp
     rhs = dble( [0,0,5,0,0] )
 
-    dirichlet = .false._1 
-    dirichlet([1,5]) = .true._1
+    dirichlet = .false._int8
+    dirichlet([1,5]) = .true._int8
 
     call stdlib_solve_pcg_custom(laplacian_csr, rhs, x, tol=1.d-6, di=dirichlet)
     print *, x !> solution: [0.0, 2.5, 5.0, 2.5, 0.0]