--- core/fpdfapi/page/cpdf_sampledfunc.cpp	2023-12-15 23:27:10.955659091 +0100
+++ core/fpdfapi/page/cpdf_sampledfunc.cpp	2023-12-15 23:27:43.420136476 +0100
@@ -17,8 +17,11 @@
 #include "core/fxcrt/compiler_specific.h"
 #include "core/fxcrt/fx_memory_wrappers.h"
 #include "core/fxcrt/fx_safe_types.h"
+#ifdef USE_SYSTEM_ABSEIL
+#include <absl/container/inlined_vector.h>
+#else
 #include "third_party/abseil-cpp/absl/container/inlined_vector.h"
-
+#endif
 namespace {
 
 // See PDF Reference 1.7, page 170, table 3.36.
diff -urN pdfium-old/core/fpdfdoc/cpdf_nametree.cpp pdfium/core/fpdfdoc/cpdf_nametree.cpp
--- core/fpdfdoc/cpdf_nametree.cpp	2025-10-13 21:48:18.759905514 +0200
+++ core/fpdfdoc/cpdf_nametree.cpp	2025-10-13 22:00:01.912909396 +0200
@@ -18,7 +18,11 @@
 #include "core/fxcrt/check.h"
 #include "core/fxcrt/ptr_util.h"
 #include "core/fxcrt/stl_util.h"
+#ifdef USE_SYSTEM_ABSEIL
+#include <absl/container/flat_hash_set.h>
+#else
 #include "third_party/abseil-cpp/absl/container/flat_hash_set.h"
+#endif
 
 namespace {