Add mysql_release.cmake intended for use by the build team (
compile options, build settings to do MySQL releases)

(handle dependent options, allow user with change WITH_READLINE to
WITH_LIBEDIT and other way around after the first compile)

Part IV: sql instrumentation

in mysqld--help test.

When mysql is compiled with different options,columns
might have different size (this depends on parameter 
names and some parameters might only be available 
when some option is switched on)

(i.e if gcc version < 4)

when EXTRA_DEBUG is enabled. The reason for the error message is that a query 
was issued with send, but response was not read with reap.

 
- backported code that handles %f/%g arguments in 
my_vsnprintf.c from 6.0 
- backported %f/%g tests in unittest/mysys/my_vsnprintf-t.c 
from 6.0 
- replaced snprintf("%g") in sql/set_var.cc with my_gcvt() 
- removed unnecessary "--replace-result"s for Windows in 
mysql-test/suite/sys_vars/t/long_query_time_basic.test 
- some test results adjustments

Unlike other platforms --mfpmath=sse is the default 
gcc mode on Mac OS X Intel. So it is unnecessary
to switch FPU to double precision mode (in fact,
it even breaks some math library functions).

Conflicts:
  - storage/myisam/mi_static.c