libc: io: implement putchar

lib/libc/include/stdio.h

@@ -53,6 +53,7 @@ static inline int putc(int c, FILE *stream)
 {
 	return fputc(c, stream);
 }
+extern int putchar(int c);
 
 extern char *fgets(char *restrict str, int count, FILE *restrict stream);
 extern int fputs(const char *restrict str, FILE *restrict stream);

lib/libc/io/stdio/putchar.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int putchar(int c)
+{
+	return fputc(c, stdout);
+}