Misc minor simplifications in C code.

* src/buffer.c (Fset_buffer_multibyte): Signal an error instead of widening.
(Fmake_overlay): Remove redundant tests.
* src/coding.h (ENCODE_FILE, DECODE_FILE, DECODE_SYSTEM): Remove special
case for the special 0 coding-system.
* src/frame.c (Fmake_terminal_frame): Prefer safer CONSP over !NILP.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/frame.c b/src/frame.c
index edb90038a48..2fcf7275f9c 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -632,7 +632,7 @@ affects all frames on the same terminal device.  */)
     Lisp_Object terminal;
 
     terminal = Fassq (Qterminal, parms);
-    if (!NILP (terminal))
+    if (CONSP (terminal))
       {
         terminal = XCDR (terminal);
         t = get_terminal (terminal, 1);