Subzero, Wasm: Link and run torture tests; bug fixes.

wasm-tests/hello-putchar.c

Index: wasm-tests/hello-putchar.c
diff --git a/wasm-tests/hello-putchar.c b/wasm-tests/hello-putchar.c
new file mode 100644
index 0000000000000000000000000000000000000000..fdeaa3bb9983bcfed2826b2e5784c52703d1cf85
--- /dev/null
+++ b/wasm-tests/hello-putchar.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+void write_int_(int fd, int n) {
+  if (n > 0) {
+    write_int_(fd, n / 10);
+
+    int rem = n % 10;
+    char c = '0' + rem;
+    write(fd, &c, 1);
+  }
+}
+
+void write_int(int fd, int n) {
+  if (n == 0) {
+    write(fd, "0", 1);
+  } else {
+    if (n < 0) {
+      write(fd, "-", 1);
+      write_int_(fd, -n);
+    } else {
+      write_int_(fd, n);
+    }
+  }
+}
+
+void stderr_int(int n) {
+  write_int(2, n);
+  write(2, "\n", 1);
+}
+
+int main(int argc, const char **argv) {
+  char *str = "Hello, World!\n";
+  for (int i = 0; str[i]; ++i) {
+    putchar(str[i]);
+  }
+  return 0;
+}