diff -Naur mysql-4.1.9/bdb/dbinc/mutex.h mysql-4.1.9.oden/bdb/dbinc/mutex.h
--- mysql-4.1.9/bdb/dbinc/mutex.h	2005-01-11 23:06:01.000000000 +0100
+++ mysql-4.1.9.oden/bdb/dbinc/mutex.h	2005-01-30 20:39:14.327183645 +0100
@@ -693,6 +693,31 @@
 #endif
 #endif
 
+/*********************************************************************
+ * amd64/gcc assembly.
+ *********************************************************************/
+#ifdef HAVE_MUTEX_X86_64_GCC_ASSEMBLY
+typedef unsigned char tsl_t;
+
+#ifdef LOAD_ACTUAL_MUTEX_CODE
+/*
+ * For gcc/amd64, 0 is clear, 1 is set.
+ */
+#define  MUTEX_SET(tsl) ({           \
+	register tsl_t *__l = (tsl);          \
+	int __r;              \
+	asm volatile("mov $1,%%rax; lock; xchgb %1,%%al; xor $1,%%rax"\
+		: "=&a" (__r), "=m" (*__l)          \
+		: "1" (*__l)            \
+		);                \
+	__r & 1;              \
+})
+
+#define  MUTEX_UNSET(tsl)  (*(tsl) = 0)
+#define  MUTEX_INIT(tsl)   MUTEX_UNSET(tsl)
+#endif
+#endif
+
 /*
  * Mutex alignment defaults to one byte.
  *
diff -Naur mysql-4.1.9/bdb/dist/aclocal/mutex.ac mysql-4.1.9.oden/bdb/dist/aclocal/mutex.ac
--- mysql-4.1.9/bdb/dist/aclocal/mutex.ac	2005-01-11 23:06:02.000000000 +0100
+++ mysql-4.1.9.oden/bdb/dist/aclocal/mutex.ac	2005-01-30 20:39:50.869954298 +0100
@@ -425,6 +425,17 @@
 ], [db_cv_mutex="S390/gcc-assembly"])
 fi
 
+# AMD64/gcc: FreeBSD, NetBSD, BSD/OS, Linux
+if test "$db_cv_mutex" = no; then
+AC_TRY_COMPILE(,[
+#if (defined(x86_64) || defined(__x86_64__)) && defined(__GNUC__)
+	exit(0);
+#else
+	FAIL TO COMPILE/LINK
+#endif
+], [db_cv_mutex="x86_64/gcc-assembly"])
+fi
+
 # ia86/gcc: Linux
 if test "$db_cv_mutex" = no; then
 AC_TRY_COMPILE(,[
@@ -570,6 +581,10 @@
 			AC_DEFINE(HAVE_MUTEX_X86_GCC_ASSEMBLY)
 			AH_TEMPLATE(HAVE_MUTEX_X86_GCC_ASSEMBLY,
 			    [Define to 1 to use the GCC compiler and x86 assembly language mutexes.]);;
+x86_64/gcc-assembly)	ADDITIONAL_OBJS="mut_tas${o} $ADDITIONAL_OBJS"
+			AC_DEFINE(HAVE_MUTEX_X86_64_GCC_ASSEMBLY)
+			AH_TEMPLATE(HAVE_MUTEX_X86_64_GCC_ASSEMBLY,
+			    [Define to 1 to use the GCC compiler and amd64 assembly language mutexes.]);;
 UNIX/fcntl)		AC_MSG_WARN(
 			    [NO FAST MUTEXES FOUND FOR THIS COMPILER/ARCHITECTURE.])
 			ADDITIONAL_OBJS="mut_fcntl${o} $ADDITIONAL_OBJS"