Build Mmap.hh even if memory mapping is disabled

Build flag `ZK_ENABLE_MMAP` no longer excludes relevant header and implementation files from build
 -> Users of ZenKit can now use Mmap.hh by themselves even if `ZK_ENABLE_MMAP` is `OFF`

Author: Katharsas

CMakeLists.txt

@@ -112,17 +112,18 @@ bs_check_posix_mmap(_ZK_HAS_MMAP_POSIX)
 bs_check_win32_mmap(_ZK_HAS_MMAP_WIN32)
 
 if (ZK_ENABLE_MMAP AND (_ZK_HAS_MMAP_POSIX OR _ZK_HAS_MMAP_WIN32))
-    if (_ZK_HAS_MMAP_POSIX)
-        message(STATUS "ZenKit: Building with POSIX memory mapping support")
-        list(APPEND _ZK_SOURCES src/MmapPosix.cc)
-        target_compile_definitions(zenkit PUBLIC _ZK_WITH_MMAP=1)
-    elseif (_ZK_HAS_MMAP_WIN32)
-        message(STATUS "ZenKit: Building with Windows memory mapping support")
-        list(APPEND _ZK_SOURCES src/MmapWin32.cc)
-        target_compile_definitions(zenkit PUBLIC _ZK_WITH_MMAP=1)
-    endif ()
+    message(WARNING "ZenKit: Memory mapping enabled")
+    target_compile_definitions(zenkit PUBLIC _ZK_WITH_MMAP=1)
 else ()
-    message(WARNING "ZenKit: Building WITHOUT memory mapping support")
+    message(WARNING "ZenKit: Memory mapping DISABLED")
+endif ()
+
+if (_ZK_HAS_MMAP_POSIX)
+    message(STATUS "ZenKit: Building with POSIX memory mapping support")
+    list(APPEND _ZK_SOURCES src/MmapPosix.cc)
+elseif (_ZK_HAS_MMAP_WIN32)
+    message(STATUS "ZenKit: Building with Windows memory mapping support")
+    list(APPEND _ZK_SOURCES src/MmapWin32.cc)
 endif ()
 
 target_sources(zenkit PRIVATE ${_ZK_SOURCES} ${_ZK_HEADERS})

include/zenkit/Mmap.hh

@@ -4,7 +4,6 @@
 #include <filesystem>
 
 namespace zenkit {
-#ifdef _ZK_WITH_MMAP
 	class Mmap {
 	public:
 		explicit Mmap(std::filesystem::path const& path);
@@ -28,5 +27,4 @@ namespace zenkit {
 
 		void* _m_platform_handle {nullptr};
 	};
-#endif
 } // namespace zenkit