ldso: silence warnings in debug code

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
buildsys: check LDFLAGS through driver

We run the linker through the compiler-driver, so we have to check
linker flags through the driver, too.
Otherwise we might check $LD's flags while we will run $CC's linker
and those might be different beasts.

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
buildsys: update unifdef

sync up to 55501a61dd257e941d53f175350ee52fc6ff2866
(2.9 + refactor keyword and symbol matching)

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
buildsys: add TODO reminder

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>