Enable to use BH_VPRINTF macro to redirect stdout output (#560)

Enable to use BH_VPRINTF macro for platform Linux/Windows/Darwin/VxWorks to redirect the stdout output from platform os_printf/os_vprintf, or the wasi output from wasm app to the vprintf like callback function specified by BH_VPRINTF macro of cmake WAMR_BH_VPRINTF variable.

Signed-off-by: Wenyong Huang <wenyong.huang@intel.com>

core/shared/platform/windows/platform_init.c

@@ -16,3 +16,30 @@ bh_platform_destroy()
 {
 }
 
+int
+os_printf(const char *format, ...)
+{
+    int ret = 0;
+    va_list ap;
+
+    va_start(ap, format);
+#ifndef BH_VPRINTF
+    ret += vprintf(format, ap);
+#else
+    ret += BH_VPRINTF(format, ap);
+#endif
+    va_end(ap);
+
+    return ret;
+}
+
+int
+os_vprintf(const char *format, va_list ap)
+{
+#ifndef BH_VPRINTF
+    return vprintf(format, ap);
+#else
+    return BH_VPRINTF(format, ap);
+#endif
+}
+

core/shared/platform/windows/platform_internal.h

@@ -49,9 +49,6 @@ typedef struct {
     unsigned int waiting_count;
 } korp_cond;
 
-#define os_printf printf
-#define os_vprintf vprintf
-
 static inline size_t
 getpagesize()
 {