Cleanup and refactoring of the STM32w port

This is a general cleanup of things like code style issues and code structure of the STM32w port to make it more like the rest of Contiki is structured.

cpu/stm32w108/e_stdio/src/small-wcrtomb.c

@@ -0,0 +1,59 @@
+#include <reent.h>
+#include <wchar.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+
+#if defined( _SMALL_PRINTF ) || defined(SMALL_SCANF) 
+#define _ASCII_CAR
+#endif
+
+size_t
+_DEFUN (_wcrtomb_r, (ptr, s, wc, ps),
+	struct _reent *ptr _AND
+	char *s _AND
+	wchar_t wc _AND
+	mbstate_t *ps)
+{
+
+#ifndef _ASCII_CAR
+  int retval = 0; 
+  char buf[10];
+
+
+#ifdef MB_CAPABLE
+  if (ps == NULL)
+    {
+      _REENT_CHECK_MISC(ptr);
+      ps = &(_REENT_WCRTOMB_STATE(ptr));
+    }
+#endif
+
+  if (s == NULL)
+    retval = _wctomb_r (ptr, buf, L'\0', ps);
+  else
+    retval = _wctomb_r (ptr, s, wc, ps);
+
+  if (retval == -1)
+    {
+      ps->__count = 0;
+      ptr->_errno = EILSEQ;
+      return (size_t)(-1);
+    }
+  else
+    return (size_t)retval;
+#endif    
+   int retval = 1 ;
+   return (size_t)retval;
+}
+
+#ifndef _REENT_ONLY
+size_t
+_DEFUN (wcrtomb, (s, wc, ps),
+	char *s _AND
+	wchar_t wc _AND
+	mbstate_t *ps)
+{
+  return _wcrtomb_r (_REENT, s, wc, ps);
+}
+#endif /* !_REENT_ONLY */