branches/zip:

Update comment to reflect reality.

include/ut0auxconf.h

 /* Do not remove this file even though it is empty.
 This file is included in univ.i and will cause compilation failure
 if not present.
-A custom check has been added in the generated
+A custom checks have been added in the generated
 storage/innobase/Makefile.in that is shipped with the InnoDB Plugin
-source archive. This check tries to compile a test program and if
-successful then adds "#define HAVE_ATOMIC_PTHREAD_T" to this file.
-This is a hack that has been developed in order to check for pthread_t
-atomicity without the need to regenerate the ./configure script that is
+source archive. These checks eventually define some macros and put
+them in this file.
+This is a hack that has been developed in order to deploy new compile
+time checks without the need to regenerate the ./configure script that is
 distributed in the MySQL 5.1 official source archives.
 If by any chance Makefile.in and ./configure are regenerated and thus
-the hack from Makefile.in wiped away then the "real" check from plug.in
+the hack from Makefile.in wiped away then the "real" checks from plug.in
 will take over.
 */