--- mysql-5.0.81/innobase/include/sync0rw.h~	2009-05-26 00:35:13.000000000 +0300
+++ mysql-5.0.81/innobase/include/sync0rw.h	2009-06-16 19:09:27.587270045 +0300
@@ -421,12 +421,6 @@
 #ifdef HAVE_ATOMIC_BUILTINS
 /* This value means NOT_LOCKED */
 #define RW_LOCK_BIAS		0x00100000
-#else
-#error HAVE_ATOMIC_BUILTINS is not defined. Do you use enough new GCC or compatibles?
-#error Or do you use exact options for CFLAGS?
-#error e.g. (for x86_32): "-m32 -march=i586 -mtune=i686"
-#error e.g. (for Sparc_64): "-m64 -mcpu=v9"
-#error Otherwise, this build may be slower than normal version.
 #endif
 
 /* NOTE! The structure appears here only for the compiler to know its size.



NOTE: this chunk is to fix buggy percona patch:
--- mysql-5.0.83/innobase/sync/sync0rw.c~	2009-07-16 12:43:34.863559101 +0300
+++ mysql-5.0.83/innobase/sync/sync0rw.c	2009-07-16 13:01:55.553904932 +0300
@@ -626,10 +626,14 @@
 	} else if (state == RW_LOCK_NOT_LOCKED) {
 
  		/* Spin waiting for the writer field to become free */
-
+#ifdef  HAVE_ATOMIC_BUILTINS
         	while (i < SYNC_SPIN_ROUNDS
 			&& lock->lock_word != RW_LOCK_BIAS) {
-        		if (srv_spin_wait_delay) {
+#else
+				while (rw_lock_get_writer(lock) != RW_LOCK_NOT_LOCKED
+						&& i < SYNC_SPIN_ROUNDS) {
+#endif
+				if (srv_spin_wait_delay) {
 				ut_delay(ut_rnd_interval(0,
 							srv_spin_wait_delay));
         		}