--- Source/bmalloc/libpas/src/libpas/pas_mar_report_crash.c.orig
+++ Source/bmalloc/libpas/src/libpas/pas_mar_report_crash.c
@@ -35,6 +35,11 @@
 
 #include <malloc/malloc.h>
 
+/* KERN_NOT_FOUND was added after the macOS 10.14 SDK (value 56). */
+#ifndef KERN_NOT_FOUND
+#define KERN_NOT_FOUND 56
+#endif
+
 PAS_BEGIN_EXTERN_C;
 
 kern_return_t pas_mar_populate_crash_report(pas_mar_crash_report* report, const char* error_type, const char* confidence,
--- Source/bmalloc/libpas/src/libpas/pas_report_crash.c.orig
+++ Source/bmalloc/libpas/src/libpas/pas_report_crash.c
@@ -33,6 +33,11 @@
 #include "pas_report_crash.h"
 #include "pas_probabilistic_guard_malloc_allocator.h"
 
+/* KERN_NOT_FOUND was added after the macOS 10.14 SDK (value 56). */
+#ifndef KERN_NOT_FOUND
+#define KERN_NOT_FOUND 56
+#endif
+
 #ifdef __APPLE__
 static void* pas_enumerator_reader_adapter(pas_enumerator* enumerator,
                                            void* remote_address, size_t size, void* arg)