wio: Turn w_print() and w_printerr() into inlines

Make w_print() and w_printerr() be "static inline" functions,
instead of variadic macros, for better type safety and compiler
error reporting. W_FUNCTION_ATTR_WARN_UNUSED_RESULT is not used
with those functions, as it is quite common to ignore I/O errors
when printing messages to stdout/stderr anyway.

doc/wio.rst

@@ -249,15 +249,15 @@ Functions
 
    See :ref:`formatted-output` for more information.
 
-.. c:function:: void w_print (format, ...)
+.. c:function:: w_io_result_t w_print (format, ...)
 
    Writes data in the given `format` to the standard output stream
    ``w_stdout``. The amount of consumed arguments depends on the
    `format` string.
 
    See :ref:`formatted-output` for more information.
 
-.. c:function:: void w_printerr (format, ...)
+.. c:function:: w_io_result_t w_printerr (format, ...)
 
    Writes data in the given `format` to the standard error stream
    ``w_stderr``. The amount of consumed arguments depends on the

wheel.h

@@ -1521,10 +1521,32 @@ W_EXPORT w_io_result_t w_io_format_ulong_oct (w_io_t *io, unsigned long value)
     W_FUNCTION_ATTR_WARN_UNUSED_RESULT
     W_FUNCTION_ATTR_NOT_NULL ((1));
 
-#define w_print(...) \
-        W_IO_NORESULT (w_io_format (w_stdout, __VA_ARGS__))
-#define w_printerr(...) \
-        W_IO_NORESULT (w_io_format (w_stderr, __VA_ARGS__))
+static inline w_io_result_t w_print (const char *format, ...)
+    W_FUNCTION_ATTR_NOT_NULL ((1));
+
+static inline w_io_result_t
+w_print (const char *format, ...)
+{
+    va_list args;
+    va_start (args, format);
+    w_io_result_t r = w_io_formatv (w_stdout, format, args);
+    va_end (args);
+    return r;
+}
+
+static inline w_io_result_t w_printerr (const char *format, ...)
+    W_FUNCTION_ATTR_NOT_NULL ((1));
+
+static inline w_io_result_t
+w_printerr (const char *format, ...)
+{
+    va_list args;
+    va_start (args, format);
+    w_io_result_t r = w_io_formatv (w_stderr, format, args);
+    va_end (args);
+    return r;
+}
+
 
 /*!
  * Reads formatted input from an I/O object.

wio.c

@@ -545,7 +545,7 @@ w_io_formatv (w_io_t *io, const char *fmt, va_list args)
 }
 
 
-/*~f void w_print (format, ...)
+/*~f w_io_result_t w_print (format, ...)
  *
  * Writes data in the given `format` to the standard output stream
  * ``w_stdout``. The amount of consumed arguments depends on the
@@ -554,7 +554,7 @@ w_io_formatv (w_io_t *io, const char *fmt, va_list args)
  * See :ref:`formatted-output` for more information.
  */
 
-/*~f void w_printerr (format, ...)
+/*~f w_io_result_t w_printerr (format, ...)
  *
  * Writes data in the given `format` to the standard error stream
  * ``w_stderr``. The amount of consumed arguments depends on the