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-wcsrtombs.c

@@ -0,0 +1,97 @@
+#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 (_wcsrtombs_r, (r, dst, src, len, ps),
+	struct _reent *r _AND
+	char *dst _AND
+	const wchar_t **src _AND
+	size_t len _AND
+	mbstate_t *ps)
+{
+  
+  
+  char *ptr = dst;
+  char buff[10];
+  wchar_t *pwcs;
+  size_t n;
+  int i;
+
+#ifdef MB_CAPABLE
+  if (ps == NULL)
+    {
+      _REENT_CHECK_MISC(r);
+      ps = &(_REENT_WCSRTOMBS_STATE(r));
+    }
+#endif
+
+  /* If no dst pointer, treat len as maximum possible value. */
+  if (dst == NULL)
+    len = (size_t)-1;
+
+  n = 0;
+  pwcs = (wchar_t *)(*src);
+
+  while (n < len)
+    {
+      int count = ps->__count;
+      wint_t wch = ps->__value.__wch;
+      #ifndef _ASCII_CAR
+      int bytes = _wcrtomb_r (r, buff, *pwcs, ps);      
+      if (bytes == -1)
+	{
+	  r->_errno = EILSEQ;
+	  ps->__count = 0;
+	  return (size_t)-1;
+	}
+	    #else
+        int bytes = 1 ;
+       #endif
+	
+      if (n <= len - bytes && bytes < len)
+	{
+          n += bytes;
+	  if (dst)
+	    {
+	      for (i = 0; i < bytes; ++i)
+	        *ptr++ = buff[i];
+	      ++(*src);
+	    }
+	  if (*pwcs++ == 0x00)
+	    {
+	      if (dst)
+	        *src = NULL;
+	      ps->__count = 0;
+	      return n - 1;
+	    }
+	}
+      else
+	{
+	  /* not enough room, we must back up state to before _wctomb_r call */
+	  ps->__count = count;
+	  ps->__value.__wch = wch;
+          len = 0;
+	}
+    }
+
+  return n;
+} 
+
+#ifndef _REENT_ONLY
+size_t
+_DEFUN (wcsrtombs, (dst, src, len, ps),
+	char *dst _AND
+	const wchar_t **src _AND
+	size_t len _AND
+	mbstate_t *ps)
+{
+  return _wcsrtombs_r (_REENT, dst, src, len, ps);
+}
+#endif /* !_REENT_ONLY */