diff --git a/src/eval-apply.c b/src/eval-apply.c
index c5f47801..d0a8a463 100644
--- a/src/eval-apply.c
+++ b/src/eval-apply.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -230,19 +230,22 @@ formal_p (struct scm *x, struct scm *formals)   /*:((internal)) */
 struct scm *
 expand_variable_ (struct scm *x, struct scm *formals, int top_p)        /*:((internal)) */
 {
+  struct scm *a;
+  struct scm *f;
+  struct scm *v;
   while (x->type == TPAIR)
     {
-      struct scm *a = x->car;
+      a = x->car;
       if (a->type == TPAIR)
         {
           if (a->car == cell_symbol_lambda)
             {
-              struct scm *f = a->cdr->car;
+              f = a->cdr->car;
               formals = add_formals (formals, f);
             }
           else if (a->car == cell_symbol_define || a->car == cell_symbol_define_macro)
             {
-              struct scm *f = a->cdr->car;
+              f = a->cdr->car;
               formals = add_formals (formals, f);
             }
           if (a->car != cell_symbol_quote)
@@ -252,13 +255,13 @@ expand_variable_ (struct scm *x, struct scm *formals, int top_p)        /*:((int
         {
           if (a == cell_symbol_lambda)
             {
-              struct scm *f = x->cdr->car;
+              f = x->cdr->car;
               formals = add_formals (formals, f);
               x = x->cdr;
             }
           else if (a == cell_symbol_define || a == cell_symbol_define_macro)
             {
-              struct scm *f = x->cdr->car;
+              f = x->cdr->car;
               if (top_p != 0 && f->type == TPAIR)
                 f = f->cdr;
               formals = add_formals (formals, f);
@@ -272,7 +275,7 @@ expand_variable_ (struct scm *x, struct scm *formals, int top_p)        /*:((int
                    && a != cell_symbol_primitive_load
                    && formal_p (x->car, formals) == 0)
             {
-              struct scm *v = module_variable (R0, a);
+              v = module_variable (R0, a);
               if (v != cell_f)
                 x->car = make_variable_ (v);
             }
@@ -293,17 +296,18 @@ struct scm *
 apply_builtin (struct scm *fn, struct scm *x)   /*:((internal)) */
 {
   struct scm *a = builtin_arity (fn);
+  struct scm *d;
   int arity = a->value;
   if ((arity > 0 || arity == -1) && x != cell_nil)
     {
-      struct scm *a = x->car;
+      a = x->car;
       if (a->type == TVALUES)
         x = cons (a->cdr->car, x->cdr);
     }
   if ((arity > 1 || arity == -1) && x != cell_nil)
     {
-      struct scm *a = x->car;
-      struct scm *d = x->cdr;
+      a = x->car;
+      d = x->cdr;
       if (d->type == TPAIR)
         if (d->car->type == TVALUES)
           x = cons (a, cons (d->car->cdr->car, d));
diff --git a/src/gc.c b/src/gc.c
index 57b7359d..89ba9d8c 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -361,11 +361,16 @@ gc_cellcpy (struct scm *dest, struct scm *src, size_t n)
   void *p = src;
   void *q = dest;
   long dist = p - q;
+  long t;
+  long a;
+  long d;
+  int i;
+  int c;
   while (n != 0)
     {
-      long t = src->type;
-      long a = src->car_value;
-      long d = src->cdr_value;
+      t = src->type;
+      a = src->car_value;
+      d = src->cdr_value;
       dest->type = t;
       if (t == TBROKEN_HEART)
         assert_msg (0, "gc_cellcpy: broken heart");
@@ -412,9 +417,9 @@ gc_cellcpy (struct scm *dest, struct scm *src, size_t n)
               eputs (cell_bytes (dest));
               eputs ("\n");
             }
-          int i = bytes_cells (a);
+          i = bytes_cells (a);
           n = n - i;
-          int c = i * M2_CELL_SIZE;
+          c = i * M2_CELL_SIZE;
           dest = dest + c;
           src = src + c;
         }
@@ -519,9 +524,10 @@ gc_loop (struct scm *scan)
 {
   struct scm *car;
   struct scm *cdr;
+  long t;
   while (scan < g_free)
     {
-      long t = scan->type;
+      t = scan->type;
       if (t == TBROKEN_HEART)
         assert_msg (0, "gc_loop: broken heart");
       /* *INDENT-OFF* */
@@ -739,6 +745,12 @@ gc_dump_arena (struct scm *cells, long size)
 {
   struct scm *end = g_cells + (size * M2_CELL_SIZE);
   struct scm *dist = cells;
+  int i;
+  long t;
+  long a;
+  long d;
+  int c;
+  char* p;
   if (g_dump_filedes == 0)
     g_dump_filedes = mes_open ("dump.mo", O_CREAT|O_WRONLY, 0644);
   dumps ("stack="); dumps (ltoa (g_stack)); dumpc ('\n');
@@ -752,12 +764,11 @@ gc_dump_arena (struct scm *cells, long size)
     }
   while (size > 0)
     {
-      int i;
       for (i=0; i < 16; i = i + 1)
         {
-          long t = cells->type;
-          long a = cells->car_value;
-          long d = cells->cdr_value;
+          t = cells->type;
+          a = cells->car_value;
+          d = cells->cdr_value;
           if (size == 0)
             dumps ("0 0 0");
           else
@@ -800,8 +811,8 @@ gc_dump_arena (struct scm *cells, long size)
                 }
               if (t == TBYTES)
                 {
-                  int c = bytes_cells (a);
-                  char *p = cell_bytes (cells);
+                  c = bytes_cells (a);
+                  p = cell_bytes (cells);
                   size = size - c;
                   dumpc ('"');
                   while (a > 0)
diff --git a/src/hash.c b/src/hash.c
index 64305879..ed1bb5d2 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -156,9 +156,10 @@ hash_table_printer (struct scm *table)
   struct scm *buckets = struct_ref_ (table, 4);
   fdputs ("buckets: ", __stdout);
   int i;
+  struct scm *e;
   for (i = 0; i < buckets->length; i = i + 1)
     {
-      struct scm *e = vector_ref_ (buckets, i);
+      e = vector_ref_ (buckets, i);
       if (e != cell_unspecified)
         {
           fdputc ('[', __stdout);
diff --git a/src/lib.c b/src/lib.c
index c0f2ad87..f8925536 100644
--- a/src/lib.c
+++ b/src/lib.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -103,6 +103,10 @@ memq (struct scm *x, struct scm *a)
 struct scm *
 equal2_p (struct scm *a, struct scm *b)
 {
+  long i;
+  struct scm *ai;
+  struct scm *bi;
+
 equal2:
   if (a == b)
     return cell_t;
@@ -122,11 +126,10 @@ equal2:
     {
       if (a->length != b->length)
         return cell_f;
-      long i;
       for (i = 0; i < a->length; i = i + 1)
         {
-          struct scm *ai = cell_ref (a->vector, i);
-          struct scm *bi = cell_ref (b->vector, i);
+          ai = cell_ref (a->vector, i);
+          bi = cell_ref (b->vector, i);
           if (ai->type == TREF)
             ai = ai->ref;
           if (bi->type == TREF)
diff --git a/src/math.c b/src/math.c
index befe60cc..ba188422 100644
--- a/src/math.c
+++ b/src/math.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  * Copyright © 2021 W. J. van der Laan <laanwj@protonmail.com>
  *
  * This file is part of GNU Mes.
@@ -45,11 +45,13 @@ greater_p (struct scm *x)               /*:((name . ">") (arity . n)) */
   assert_number ("greater_p", x->car);
   long n = x->car->value;
   x = x->cdr;
+  struct scm *i;
+  long v;
   while (x != cell_nil)
     {
       assert_number ("greater_p", x->car);
-      struct scm *i = car (x);
-      long v = i->value;
+      i = car (x);
+      v = i->value;
       if (v >= n)
         return cell_f;
       n = v;
@@ -66,11 +68,13 @@ less_p (struct scm *x)                  /*:((name . "<") (arity . n)) */
   assert_number ("less_p", x->car);
   long n = x->car->value;
   x = x->cdr;
+  struct scm *i;
+  long v;
   while (x != cell_nil)
     {
       assert_number ("less_p", x->car);
-      struct scm *i = car (x);
-      long v = i->value;
+      i = car (x);
+      v = i->value;
       if (v <= n)
         return cell_f;
       n = v;
@@ -87,10 +91,12 @@ is_p (struct scm *x)                    /*:((name . "=") (arity . n)) */
   assert_number ("is_p", x->car);
   long n = x->car->value;
   x = cdr (x);
+  struct scm *i;
+  long v;
   while (x != cell_nil)
     {
-      struct scm *i = car (x);
-      long v = i->value;
+      i = car (x);
+      v = i->value;
       if (v != n)
         return cell_f;
       x = cdr (x);
@@ -106,11 +112,13 @@ minus (struct scm *x)                   /*:((name . "-") (arity . n)) */
   x = cdr (x);
   if (x == cell_nil)
     n = -n;
+  struct scm *i;
+  long v;
   while (x != cell_nil)
     {
-      struct scm *i = car (x);
+      i = car (x);
       assert_number ("minus", i);
-      long v = i->value;
+      v = i->value;
       n = n - v;
       x = cdr (x);
     }
@@ -121,11 +129,13 @@ struct scm *
 plus (struct scm *x)                    /*:((name . "+") (arity . n)) */
 {
   long n = 0;
+  struct scm *i;
+  long v;
   while (x != cell_nil)
     {
-      struct scm *i = car (x);
+      i = car (x);
       assert_number ("plus", i);
-      long v = i->value;
+      v = i->value;
       n = n + v;
       x = cdr (x);
     }
@@ -136,19 +146,21 @@ struct scm *
 divide (struct scm *x)                  /*:((name . "/") (arity . n)) */
 {
   long n = 1;
+  struct scm *i;
+  long v;
   if (x != cell_nil)
     {
-      struct scm *i = car (x);
+      i = car (x);
       assert_number ("divide", i);
-      long v = i->value;
+      v = i->value;
       n = v;
       x = cdr (x);
     }
   while (x != cell_nil)
     {
-      struct scm *i = car (x);
+      i = car (x);
       assert_number ("divide", i);
-      long v = i->value;
+      v = i->value;
       if (v == 0)
         error (cstring_to_symbol ("divide-by-zero"), x);
       if (n == 0)
@@ -180,11 +192,13 @@ struct scm *
 multiply (struct scm *x)                /*:((name . "*") (arity . n)) */
 {
   long n = 1;
+  struct scm *i;
+  long v;
   while (x != cell_nil)
     {
-      struct scm *i = car (x);
+      i = car (x);
       assert_number ("multiply", i);
-      long v = i->value;
+      v = i->value;
       n = n * v;
       x = cdr (x);
     }
@@ -195,11 +209,13 @@ struct scm *
 logand (struct scm *x)                  /*:((arity . n)) */
 {
   long n = -1;
+  struct scm *i;
+  long v;
   while (x != cell_nil)
     {
-      struct scm *i = car (x);
+      i = car (x);
       assert_number ("multiply", i);
-      long v = i->value;
+      v = i->value;
       n = n & v;
       x = cdr (x);
     }
@@ -210,11 +226,13 @@ struct scm *
 logior (struct scm *x)                  /*:((arity . n)) */
 {
   long n = 0;
+  struct scm *i;
+  long v;
   while (x != cell_nil)
     {
-      struct scm *i = car (x);
+      i = car (x);
       assert_number ("logior", i);
-      long v = i->value;
+      v = i->value;
       n = n | v;
       x = cdr (x);
     }
@@ -233,11 +251,13 @@ struct scm *
 logxor (struct scm *x)                  /*:((arity . n)) */
 {
   long n = 0;
+  struct scm *i;
+  long v;
   while (x != cell_nil)
     {
-      struct scm *i = car (x);
+      i = car (x);
       assert_number ("logxor", i);
-      long v = i->value;
+      v = i->value;
       n = n ^ v;
       x = cdr (x);
     }
diff --git a/src/posix.c b/src/posix.c
index 855440c0..ed887f11 100644
--- a/src/posix.c
+++ b/src/posix.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -205,9 +205,10 @@ current_input_port ()
   if (__stdin >= 0)
     return make_number (__stdin);
   struct scm *x = g_ports;
+  struct scm *a;
   while (x != 0)
     {
-      struct scm *a = x->car;
+      a = x->car;
       if (a->port == __stdin)
         return a;
       x = x->cdr;
@@ -328,10 +329,11 @@ execl_ (struct scm *file_name, struct scm *args)        /*:((name . "execl")) */
            cons (file_name, cons (make_string0 ("too many arguments"), cons (file_name, args))));
   c_argv[i] = cell_bytes (file_name->string);
   i = i + 1;
+  struct scm *arg;
   while (args != cell_nil)
     {
       assert_msg (args->car->type == TSTRING, "args->car->type == TSTRING");
-      struct scm *arg = args->car;
+      arg = args->car;
       c_argv[i] = cell_bytes (arg->string);
       i = i + 1;
       args = args->cdr;
diff --git a/src/reader.c b/src/reader.c
index 087fae24..6b421782 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  * Copyright © 2018 Jeremiah Orians <jeremiah@pdp10.guru>
  *
  * This file is part of GNU Mes.
@@ -439,6 +439,7 @@ reader_read_string ()
 {
   size_t i = 0;
   int c;
+  struct scm *n;
   do
     {
       if (i > MAX_STRING)
@@ -475,7 +476,7 @@ reader_read_string ()
             c = 27;
           else if (c == 'x')
             {
-              struct scm *n = reader_read_hex ();
+              n = reader_read_hex ();
               c = n->value;
             }
         }
diff --git a/src/stack.c b/src/stack.c
index 6e6a961e..6fc25fb1 100644
--- a/src/stack.c
+++ b/src/stack.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  * Copyright © 2021 W. J. van der Laan <laanwj@protonmail.com>
  *
  * This file is part of GNU Mes.
@@ -81,9 +81,10 @@ make_stack (struct scm *stack)          /*:((arity . n)) */
   long size = (STACK_SIZE - g_stack) / FRAME_SIZE;
   struct scm *frames = make_vector_ (size, cell_unspecified);
   long i;
+  struct scm* frame;
   for (i = 0; i < size; i = i + 1)
     {
-      struct scm *frame = make_frame (stack, i);
+      frame = make_frame (stack, i);
       vector_set_x_ (frames, i, frame);
     }
   struct scm *values = cell_nil;
diff --git a/src/string.c b/src/string.c
index 6b3b3bbb..171cb7b5 100644
--- a/src/string.c
+++ b/src/string.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -45,11 +45,12 @@ list_to_cstring (struct scm *list, size_t *size)
 {
   size_t i = 0;
   char *p = g_buf;
+  struct scm *x;
   while (list != cell_nil)
     {
       if (i > MAX_STRING)
         assert_max_string (i, "list_to_string", g_buf);
-      struct scm *x = car (list);
+      x = car (list);
       g_buf[i] = x->value;
       i = i + 1;
       list = cdr (list);
@@ -131,10 +132,11 @@ struct scm *
 bytes_to_list (char const *s, size_t i)
 {
   struct scm *p = cell_nil;
+  int c;
   while (i != 0)
     {
       i = i - 1;
-      int c = (0x100 + s[i]) % 0x100;
+      c = (0x100 + s[i]) % 0x100;
       p = cons (make_char (c), p);
     }
   return p;
@@ -198,9 +200,10 @@ string_append (struct scm *x)           /*:((arity . n)) */
   char *p = g_buf;
   g_buf[0] = 0;
   size_t size = 0;
+  struct scm *string;
   while (x != cell_nil)
     {
-      struct scm *string = x->car;
+      string = x->car;
       assert_msg (string->type == TSTRING, "string->type == TSTRING");
       memcpy (p, cell_bytes (string->string), string->length + 1);
       p = p + string->length;
diff --git a/src/struct.c b/src/struct.c
index 1620ee22..19162c70 100644
--- a/src/struct.c
+++ b/src/struct.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -33,9 +33,10 @@ make_struct (struct scm *type, struct scm *fields, struct scm *printer)
   copy_cell (v, vector_entry (type));
   copy_cell (cell_ref (v, 1), vector_entry (printer));
   long i;
+  struct scm *e;
   for (i = 2; i < size; i = i + 1)
     {
-      struct scm *e = cell_unspecified;
+      e = cell_unspecified;
       if (fields != cell_nil)
         {
           e = fields->car;
diff --git a/src/symbol.c b/src/symbol.c
index c9598ff6..1b6850f5 100644
--- a/src/symbol.c
+++ b/src/symbol.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
diff --git a/src/vector.c b/src/vector.c
index f34220dc..0fc84040 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -127,9 +127,10 @@ vector_to_list (struct scm *v)
 {
   struct scm *x = cell_nil;
   long i;
+  struct scm *e;
   for (i = v->length; i; i = i - 1)
     {
-      struct scm *e = cell_ref (v->vector, i - 1);
+      e = cell_ref (v->vector, i - 1);
       if (e->type == TREF)
         e = e->ref;
       x = cons (e, x);