add stdio.h for definition of asprintf and vasprintf

include/Makefile.am

@@ -17,5 +17,6 @@ noinst_HEADERS += stdlib.h
 noinst_HEADERS += Makefile.in
 noinst_HEADERS += paths.h
 noinst_HEADERS += poll.h
+noinst_HEADERS += stdio.h
 noinst_HEADERS += time.h
 noinst_HEADERS += tls.h

include/stdio.h

@@ -0,0 +1,30 @@
+/*
+ * Public domain
+ * stdio.h compatibility shim
+ */
+
+#include_next <stdio.h>
+
+#ifndef LIBCRYPTOCOMPAT_STDIO_H
+#define LIBCRYPTOCOMPAT_STDIO_H
+
+#ifndef HAVE_ASPRINTF
+#include <stdarg.h>
+int vasprintf(char **str, const char *fmt, va_list ap);
+int asprintf(char **str, const char *fmt, ...);
+#endif
+
+#ifdef _WIN32
+#include <errno.h>
+#include <string.h>
+
+static inline void
+posix_perror(const char *s)
+{
+	fprintf(stderr, "%s: %s\n", s, strerror(errno));
+}
+
+#define perror(errnum) posix_perror(errnum)
+#endif
+
+#endif