Add test for unicode input/output

tests/_all/input-output/read-unicode.c

@@ -0,0 +1,30 @@
+// Make sure we can read unicode characters. This is to make sure the utilities
+// we compile using pnut-sh can process all kind of files.
+// This test is not essential for the bootstrap but being able to properly read
+// non-ascii characters makes pnut more general.
+//
+// Yash's IO is a little bit weird and it's not a very popular shell, disabling the test for now.
+// expect_failure_for: yash
+
+#ifndef PNUT_CC
+#include <stdio.h>
+#else
+typedef int FILE;
+#endif
+
+void putstr(const char *s) {
+  while (*s) {
+    putchar(*s);
+    s++;
+  }
+}
+
+void main() {
+  int i = 0;
+  char c;
+  FILE *f = fopen("tests/_all/input-output/unicode.txt", "r");
+  putstr("printf? 💣\n");
+  while ((c = fgetc(f)) != -1) {
+    putchar(c);
+  }
+}

tests/_all/input-output/read-unicode.golden

@@ -0,0 +1,3 @@
+printf? 💣
+accents: éôèà
+some emoji: 🥜

tests/_all/input-output/unicode.txt

@@ -0,0 +1,2 @@
+accents: éôèà
+some emoji: 🥜