add parallel test

tests/projects/other/parallel_build/1.cpp

@@ -0,0 +1,2 @@
+int main(){
+}

tests/projects/other/parallel_build/2.cpp

@@ -0,0 +1,31 @@
+// Make this object complex and cost longer compile time...
+#include <algorithm>
+#include <any>
+#include <bitset>
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <list>
+#include <map>
+#include <optional>
+#include <queue>
+#include <string>
+#include <unordered_map>
+#include <variant>
+#include <vector>
+
+int main() {
+
+  using Type = std::variant<int8_t, uint8_t, int16_t, uint16_t, int32_t,
+                            uint32_t, int64_t, uint64_t, double, float>;
+  Type a, b, c;
+  a = 5;
+  b = 3.0;
+  c = 4.0f;
+  double r;
+  std::visit([&](auto a, auto b, auto c) { r = a + b + c; }, a, b, c);
+  std::visit([&](auto a, auto b, auto c) { r = a + b - c; }, a, b, c);
+  std::visit([&](auto a, auto b, auto c) { r = a - b - c; }, a, b, c);
+  std::visit([&](auto a, auto b, auto c) { r = (a + b + c) * 2; }, a, b, c);
+  std::visit([&](auto a, auto b, auto c) { r = (a + b - c) * 3; }, a, b, c);
+}

tests/projects/other/parallel_build/xmake.lua

@@ -0,0 +1,13 @@
+-- These targets should compiled and linked concurrently.
+add_rules("mode.release", "mode.debug", "mode.releasedbg")
+set_policy("build.ccache", false)
+
+target("first")
+    set_kind("binary")
+    add_files("1.cpp")
+    set_languages("clatest", "cxx20")
+
+target("second")
+    set_kind("binary")
+    add_files("2.cpp")
+    set_languages("clatest", "cxx20")