test: simple multi alarm test

An intentionally simple test for multiple alarms that only sets exactly
two repeating alarms that should overlap frequently (one is twice the
other's frequency).

examples/tests/multi_alarm_simple_test/Makefile

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+# Makefile for user application
+
+# Specify this directory relative to the current application.
+TOCK_USERLAND_BASE_DIR = ../../..
+
+# Which files to compile.
+C_SRCS := $(wildcard *.c)
+
+# Include userland master makefile. Contains rules and flags for actually
+# building the application.
+include $(TOCK_USERLAND_BASE_DIR)/AppMakefile.mk

examples/tests/multi_alarm_simple_test/README.md

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+# Test Multiple Alarms (Simple)
+
+This tests the virtual alarms available to userspace. It sets two
+repeating alarms, at 500ms and 1s respectively, each prints the alarm
+index (1 or 2), current tick and alarm expiration to the console. When
+successful, both alarms should fire and alarm 1 should fire twice as
+often as alarm 2.

examples/tests/multi_alarm_simple_test/main.c

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+#include <stdlib.h>
+#include <stdio.h>
+
+#include <libtock-sync/services/alarm.h>
+
+static void event_cb(__attribute__ ((unused)) uint32_t now,
+                     __attribute__ ((unused)) uint32_t expiration,
+                     void*                             ud) {
+  int i = (int)ud;
+  printf("%d %ld %ld\n", i, now, expiration);
+}
+
+int main(void) {
+    libtock_alarm_t t1;
+    libtock_alarm_t t2;
+
+    libtock_alarm_repeating_every_ms( 500, event_cb, (void*)1, &t1);
+    libtock_alarm_repeating_every_ms(1000, event_cb, (void*)2, &t2);
+
+  while (1) {
+    yield();
+  }
+}