Fortran: Fix issue with using snprintf function.

The previous patch used snprintf to set the message
string. The message string is not a formatted string
and the snprintf will interpret '%' related characters
as format specifiers when there are no associated
output variables. A segfault ensues.

This change replaces snprintf with a fortran string copy
function and null terminates the message string.

	PR libfortran/105456

libgfortran/ChangeLog:

	* io/list_read.c (list_formatted_read_scalar): Use fstrcpy
	from libgfortran/runtime/string.c to replace snprintf.
	(nml_read_obj): Likewise.
	* io/transfer.c (unformatted_read): Likewise.
	(unformatted_write): Likewise.
	(formatted_transfer_scalar_read): Likewise.
	(formatted_transfer_scalar_write): Likewise.
	* io/write.c (list_formatted_write_scalar): Likewise.
	(nml_write_obj): Likewise.

gcc/testsuite/ChangeLog:

	* gfortran.dg/pr105456.f90: Revise using '%' characters
	in users error message.

1 files changed, 2 insertions, 2 deletions

diff --git a/gcc/testsuite/gfortran.dg/pr105456.f90 b/gcc/testsuite/gfortran.dg/pr105456.f90
index 1883238..60cd3b6 100644
--- a/gcc/testsuite/gfortran.dg/pr105456.f90
+++ b/gcc/testsuite/gfortran.dg/pr105456.f90
@@ -19,7 +19,7 @@ contains
     character :: ch
     read (unit,fmt='(A1)', advance="no", iostat=piostat, iomsg=piomsg) ch
     piostat = 42
-    piomsg="The users message"
+    piomsg="The users message containing % and %% and %s and other stuff"
     dtv%ch = ch
   end subroutine read_formatted
 end module sk1
@@ -35,4 +35,4 @@ program skip1
   write (*,'(10(A))') "Read: '",x%ch,"'"
 end program skip1
 ! { dg-output ".*(unit = 10, file = .*)" }
-! { dg-output "Fortran runtime error: The users message" }
+! { dg-output "Fortran runtime error: The users message containing % and %% and %s and other stuff" }