port more apps

hello/Makefile

@@ -0,0 +1,3 @@
+NAME = hello-am
+SRCS = hello.c
+include $(AM_HOME)/Makefile

hello/hello.c

@@ -0,0 +1,13 @@
+#include <am.h>
+#include <klib-macros.h>
+
+int main(const char *args) {
+  const char *fmt =
+    "Hello, AbstractMachine!\n"
+    "mainargs = '%'.\n";
+
+  for (const char *p = fmt; *p; p++) {
+    (*p == '%') ? putstr(args) : putch(*p);
+  }
+  return 0;
+}