tweaks for enabling unity builds

mostly changes to make sure anonymous namespaces don't clash and a change to avoid windows headers from leaking into other compilation units

unity builds are not yet enabled by default, but can be enabled by uncommenting this line in the root `xmake.lua`

```
--add_rules("c++.unity_build")
```

1 files changed, 8 insertions, 2 deletions

diff --git a/zenstore/gc.cpp b/zenstore/gc.cpp
index 8d3b8d018..370c3c965 100644
--- a/zenstore/gc.cpp
+++ b/zenstore/gc.cpp
@@ -888,7 +888,7 @@ GcScheduler::CollectGarbage(const GcClock::TimePoint& ExpireTime, bool Delete, b
 
 #if ZEN_WITH_TESTS
 
-namespace {
+namespace gc::impl {
 	static IoBuffer CreateChunk(uint64_t Size)
 	{
 		static std::random_device rd;
@@ -909,10 +909,12 @@ namespace {
 	{
 		return CompressedBuffer::Compress(SharedBuffer::MakeView(Buffer.GetData(), Buffer.GetSize()));
 	}
-}  // namespace
+}  // namespace gc::impl
 
 TEST_CASE("gc.basic")
 {
+	using namespace gc::impl;
+
 	ScopedTemporaryDirectory TempDir;
 
 	CidStoreConfiguration CasConfig;
@@ -940,6 +942,8 @@ TEST_CASE("gc.basic")
 
 TEST_CASE("gc.full")
 {
+	using namespace gc::impl;
+
 	ScopedTemporaryDirectory TempDir;
 
 	CidStoreConfiguration CasConfig;
@@ -1140,6 +1144,8 @@ TEST_CASE("gc.full")
 
 TEST_CASE("gc.diskusagewindow")
 {
+	using namespace gc::impl;
+
 	DiskUsageWindow Stats;
 	Stats.Append({.SampleTime = 0, .DiskUsage = 0});	// 0	0
 	Stats.Append({.SampleTime = 10, .DiskUsage = 10});	// 1	10