Base printf routines on one another (#248)

There should only be one printf routine present given its size, but the
inliner may inline the implementation into multiple different versions
of the function. Explicitly basing the routines on one another
discourages this.

Author: mysterymath

mos-platform/common/c/printf.c

@@ -941,24 +941,23 @@ static int _vsnprintf(out_fct_type out, char *buffer, const size_t maxlen,
 int printf(const char *format, ...) {
   va_list va;
   va_start(va, format);
-  char buffer[1];
-  const int ret = _vsnprintf(_out_char, buffer, (size_t)-1, format, va);
+  const int ret = vprintf(format, va);
   va_end(va);
   return ret;
 }
 
 int sprintf(char *buffer, const char *format, ...) {
   va_list va;
   va_start(va, format);
-  const int ret = _vsnprintf(_out_buffer, buffer, (size_t)-1, format, va);
+  const int ret = vsnprintf(buffer, (size_t)-1, format, va);
   va_end(va);
   return ret;
 }
 
 int snprintf(char *buffer, size_t count, const char *format, ...) {
   va_list va;
   va_start(va, format);
-  const int ret = _vsnprintf(_out_buffer, buffer, count, format, va);
+  const int ret = vsnprintf(buffer, count, format, va);
   va_end(va);
   return ret;
 }