compat: backport IS_ENABLED macro

compat: backport IS_ENABLED macro

IS_ENABLED(option) was backported as defined(option), but
because of the indirection, option was evaluated too early,
resulting in #if defined(1) for defined options, which failed
the compilation with the following error:

error: operator "defined" requires an identifier

Backport IS_ENABLED from the current kernel instead.

mcgrof@tux ~/compat (git::master)$ ckmake
Trying kernel                  3.4.0-030400rc1-generic	[OK]
Trying kernel                  3.3.0-030300rc2-generic	[OK]
Trying kernel                     3.2.2-030202-generic	[OK]
Trying kernel                    3.1.10-030110-generic	[OK]
Trying kernel                    3.0.18-030018-generic	[OK]
Trying kernel                  2.6.39-02063904-generic	[OK]
Trying kernel                  2.6.38-02063808-generic	[OK]
Trying kernel                  2.6.37-02063706-generic	[OK]
Trying kernel                  2.6.36-02063604-generic	[OK]
Trying kernel                  2.6.35-02063512-generic	[OK]
Trying kernel                  2.6.34-02063410-generic	[OK]
Trying kernel                  2.6.33-02063305-generic	[OK]
Trying kernel                  2.6.32-02063255-generic	[OK]
Trying kernel                  2.6.31-02063113-generic	[OK]
Trying kernel                  2.6.30-02063010-generic	[OK]
Trying kernel                  2.6.29-02062906-generic	[OK]
Trying kernel                  2.6.28-02062810-generic	[OK]
Trying kernel                    2.6.27-020627-generic	[OK]
Trying kernel                    2.6.26-020626-generic	[OK]
Trying kernel                    2.6.25-020625-generic	[OK]
Trying kernel                    2.6.24-020624-generic	[OK]

Tested-by: Luis R. Rodriguez <mcgrof@frijolero.org>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@frijolero.org>