From 959dcbfa51bdac698ffdf3dc5f6b04de504a6afb Mon Sep 17 00:00:00 2001
From: Andrew Udvare <audvare@gmail.com>
Date: Mon, 9 Feb 2026 00:19:20 -0500
Subject: [PATCH 04/23] Add USE_SYSTEM_XXHASH option for system libxxhash

- third_party/CMakeLists.txt: link system libxxhash (pkg-config) when
  USE_SYSTEM_XXHASH is set, else build the bundled copy.
- src/xenia/base/xxhash.h: include <xxhash.h> with XXH_STATIC_LINKING_ONLY
  when XENIA_USE_SYSTEM_XXHASH is defined.

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 src/xenia/base/xxhash.h    |  6 ++++++
 third_party/CMakeLists.txt | 17 +++++++++++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/xenia/base/xxhash.h b/src/xenia/base/xxhash.h
index 30960e8d5..4de81eeaa 100644
--- a/src/xenia/base/xxhash.h
+++ b/src/xenia/base/xxhash.h
@@ -10,6 +10,11 @@
 #ifndef XENIA_BASE_XXHASH_H_
 #define XENIA_BASE_XXHASH_H_
 
+#ifdef XENIA_USE_SYSTEM_XXHASH
+/* Expose XXH3_state_s definition so stack-allocated XXH3_state_t is valid. */
+#define XXH_STATIC_LINKING_ONLY
+#include <xxhash.h>
+#else
 #define XXH_INLINE_ALL
 
 // Can't use XXH_X86DISPATCH because XXH is calculated on multiple threads,
@@ -17,5 +22,6 @@
 // synchronization) to XXH_g_dispatch at the first call.
 
 #include "third_party/xxhash/xxhash.h"
+#endif
 
 #endif  // XENIA_BASE_XXHASH_H_
diff --git a/third_party/CMakeLists.txt b/third_party/CMakeLists.txt
index fcdca8bbf..34810c86e 100644
--- a/third_party/CMakeLists.txt
+++ b/third_party/CMakeLists.txt
@@ -227,10 +227,19 @@ target_include_directories(snappy PUBLIC snappy)
 # ==============================================================================
 # xxhash
 # ==============================================================================
-add_library(xxhash STATIC
-  xxhash/xxhash.c
-)
-target_include_directories(xxhash PUBLIC xxhash)
+if(USE_SYSTEM_XXHASH)
+  find_package(PkgConfig REQUIRED)
+  pkg_check_modules(XXHASH REQUIRED libxxhash)
+  add_library(xxhash INTERFACE)
+  target_include_directories(xxhash SYSTEM INTERFACE ${XXHASH_INCLUDE_DIRS})
+  target_link_libraries(xxhash INTERFACE ${XXHASH_LDFLAGS})
+  target_compile_options(xxhash INTERFACE ${XXHASH_CFLAGS_OTHER})
+else()
+  add_library(xxhash STATIC
+    xxhash/xxhash.c
+  )
+  target_include_directories(xxhash PUBLIC xxhash)
+endif()
 
 # ==============================================================================
 # zstd
-- 
2.54.0