Improve compatibility with some compilers

src/gray_errors.f90

@@ -24,7 +24,7 @@ module gray_errors
 
   ! macros used for defining errors
 # define _ ,
-# define list(x) reshape([character(64) :: x], [10], [''])
+# define list(x) reshape([character(64) :: x], [10], [character(64) :: ''])
 # define after(x) x%offset + x%subcases
 
   ! All GRAY errors

src/splines.f90

@@ -34,6 +34,11 @@ module splines
       procedure :: deriv  => spline_1d_deriv
   end type
 
+  ! Wrapper to store pointers in an array
+  type pointer
+    real(wp_), pointer :: ptr(:) => null()
+  end type
+
   ! A 2D smoothing/interpolating cubic spline s(x, y)
   type spline_2d
     integer :: nknots_x                   ! Number of x knots
@@ -54,11 +59,6 @@ module splines
       procedure :: transform  => spline_2d_transform
   end type
 
-  ! Wrapper to store pointers in an array
-  type pointer
-    real(wp_), pointer :: ptr(:) => null()
-  end type
-
   ! A simple 1D linear interpolation
   type linear_1d
     integer :: ndata                   ! Number of data points