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, 14 insertions, 2 deletions

diff --git a/zenstore/blockstore.cpp b/zenstore/blockstore.cpp
index 5d81d1120..d743c431f 100644
--- a/zenstore/blockstore.cpp
+++ b/zenstore/blockstore.cpp
@@ -859,7 +859,7 @@ TEST_CASE("blockstore.blockfile")
 	CHECK(!std::filesystem::exists(RootDirectory / "1"));
 }
 
-namespace {
+namespace blockstore::impl {
 	BlockStoreLocation WriteStringAsChunk(BlockStore& Store, std::string_view String, size_t PayloadAlignment)
 	{
 		BlockStoreLocation Location;
@@ -907,10 +907,12 @@ namespace {
 
 		return IoBufferBuilder::MakeCloneFromMemory(Values.data(), Values.size());
 	}
-}  // namespace
+}  // namespace blockstore::impl
 
 TEST_CASE("blockstore.chunks")
 {
+	using namespace blockstore::impl;
+
 	ScopedTemporaryDirectory TempDir;
 	auto					 RootDirectory = TempDir.Path();
 
@@ -939,6 +941,8 @@ TEST_CASE("blockstore.chunks")
 
 TEST_CASE("blockstore.clean.stray.blocks")
 {
+	using namespace blockstore::impl;
+
 	ScopedTemporaryDirectory TempDir;
 	auto					 RootDirectory = TempDir.Path();
 
@@ -963,6 +967,8 @@ TEST_CASE("blockstore.clean.stray.blocks")
 
 TEST_CASE("blockstore.flush.forces.new.block")
 {
+	using namespace blockstore::impl;
+
 	ScopedTemporaryDirectory TempDir;
 	auto					 RootDirectory = TempDir.Path();
 
@@ -984,6 +990,8 @@ TEST_CASE("blockstore.flush.forces.new.block")
 
 TEST_CASE("blockstore.iterate.chunks")
 {
+	using namespace blockstore::impl;
+
 	ScopedTemporaryDirectory TempDir;
 	auto					 RootDirectory = TempDir.Path();
 
@@ -1078,6 +1086,8 @@ TEST_CASE("blockstore.iterate.chunks")
 
 TEST_CASE("blockstore.reclaim.space")
 {
+	using namespace blockstore::impl;
+
 	ScopedTemporaryDirectory TempDir;
 	auto					 RootDirectory = TempDir.Path();
 
@@ -1193,6 +1203,8 @@ TEST_CASE("blockstore.reclaim.space")
 
 TEST_CASE("blockstore.thread.read.write")
 {
+	using namespace blockstore::impl;
+
 	ScopedTemporaryDirectory TempDir;
 	auto					 RootDirectory = TempDir.Path();