Move tmp::fs definition to a separate file (#24)

- Move tmp::fs definition to a separate file
- Remove <filesystem> include

include/tmp/directory

@@ -1,8 +1,8 @@
 #pragma once
 
+#include <tmp/fs>
 #include <tmp/path>
 
-#include <filesystem>
 #include <string_view>
 
 namespace tmp {

include/tmp/file

@@ -1,8 +1,8 @@
 #pragma once
 
+#include <tmp/fs>
 #include <tmp/path>
 
-#include <filesystem>
 #include <fstream>
 #include <string>
 #include <string_view>

include/tmp/fs

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <filesystem>
+
+namespace tmp {
+
+/// The filesystem library to use
+namespace fs = std::filesystem;
+}    // namespace tmp

include/tmp/path

@@ -1,13 +1,12 @@
 #pragma once
 
+#include <tmp/fs>
+
 #include <filesystem>
 #include <string_view>
 
 namespace tmp {
 
-/// The filesystem library to use
-namespace fs = std::filesystem;
-
 /// tmp::path is a smart handle that owns and manages a temporary path and
 /// deletes it recursively when this handle goes out of scope
 ///

src/tmp.cpp

@@ -1,9 +1,8 @@
+#include <tmp/fs>
 #include <tmp/path>
-
 #include <tmp/file>
 #include <tmp/directory>
 
-#include <filesystem>
 #include <fstream>
 #include <string_view>
 #include <system_error>