use bit shift to set bitflags

[divinity76]

nitpicking, this makes it practically impossible to accidentally use a number with 2 bits set in the future,
it's also my personal preference, its trivial to see "PHP_FILE_NO_DEFAULT_CONTEXT use bit 4" and that "the next unused bit is bit 5"

[divinity76]

speaking of accidentally using a number with 2 bits set, why is LOCK_UN using a number with 2 bits set in https://github.com/php/php-src/blob/master/ext/standard/flock_compat.h#L48 ? (3 / 00000011 )

a number that collide with both LOCK_SH and LOCK_EX? well now i'm confused a strange choice, now implementors must make sure to check for LOCK_UN before LOCK_SH/LOCK_EX, if an implementor accidentally check for LOCK_SH/LOCK_EX before LOCK_UN, the collision would break it ^^ and it's a choice NOT shared with C, i might add. C use 1, 2, and 8 (all of which doesn't collide and use only 1 bit), PHP use 1,2, and 3 (where 3 use 2 bits and collide with 1 and 2)

[Girgias]

speaking of accidentally using a number with 2 bits set, why is LOCK_UN using a number with 2 bits set in https://github.com/php/php-src/blob/master/ext/standard/flock_compat.h#L48 ? (3 / 00000011 )

a number that collide with both LOCK_SH and LOCK_EX? well now i'm confused a strange choice, now implementors must make sure to check for LOCK_UN before LOCK_SH/LOCK_EX, if an implementor accidentally check for LOCK_SH/LOCK_EX before LOCK_UN, the collision would break it ^^ and it's a choice NOT shared with C, i might add. C use 1, 2, and 8 (all of which doesn't collide and use only 1 bit), PHP use 1,2, and 3 (where 3 use 2 bits and collide with 1 and 2)

That looks like a bug to me then.

[divinity76]

@Girgias yeah it loosk super weird, and it breaks code like

<?php
function f(int $flags){
    if($flags & LOCK_SH){
        echo "im handling a LOCK_SH request!";
    }elseif($flags & LOCK_EX){
        echo "im handling a LOCK_EX request!";
    }elseif($flags === LOCK_UN){
        echo "im handling a LOCK_UN request!";
    }else{
        echo "didn't understand those flags...";
    }
}
f(LOCK_UN);

which is fine in C (and i guess, most languages), but in PHP produce => im handling a LOCK_SH request!