Update src/stdlib_str2num.f90

Co-authored-by: Jeremie Vandenplas <[email protected]>

Author: jalvesz

src/stdlib_str2num.f90

@@ -328,7 +328,7 @@ elemental subroutine to_real_dp(s,v,p,stat)
         integer(wp) :: int_wp !> long integer to capture fractional part
         integer     :: i_exp !> integer to capture whole number part
         integer     :: exp_aux
-        integer(1)  :: i, pP, pE, val , resp
+        integer(int8)  :: i, pP, pE, val , resp
         !----------------------------------------------
         stat = 23 !> initialize error status with any number > 0
         !----------------------------------------------