run Linuxcnc on xenomai with EVL(the realtime core)

I''ve forgotton where, but there is code that decides whether to build for rtapi or realtime.
There is a conditional that decides which type of thread to create for the servo thread. I think rtapi is decided by an environment variable.
My take was this needed to be changed to acommodate EVL and this code would need reviewing.
github.com/LinuxCNC/linuxcnc/tree/master/src/rtapi  

Thank you all for the suggestions. Unfortunately, using Xenomai 4's EVL with LinuxCNC didn't work for me; I've tried everything.
Following my instructor's advice, I switched to using Xenomai 3 for the build. （this is a topic I'm exploring）During the build process, Xenomai was successfully detected.
 
However, when running it, the real-time core of Xenomai still wasn't utilized.
 
I found some posts on the forum from a few years ago with the same issue,

forum.linuxcnc.org/9-installing-linuxcnc...ith-xenomai3?start=0

but I couldn't find a solution. Do any of you have new suggestions?

I refer here to main branch of linuxcnc 2.10 (master or devel) and it works with Xenomai 3. 

You done everything correct but apart building LinuxCNC to Xenomai the LinuxCNC at runtime checks if it has Xenomai kernel.

In order to fix the issue you must edit file: "linuxcnc/src/rtapi/uspace_common.h", around 386 line of code you find:

#ifdef USPACE_XENOMAI
static int detect_xenomai() {
    struct utsname u;
    uname(&u);
    return strcasestr (u.release, "-xenomai") != 0;
}
#else
static int detect_xenomai() {
    return 0;
}

As you see to check what kernel you got it uses very well known "uname" function. The problem is that at the moment Kernel build with Xenomai (new versions) and checked with "uname" does not include word "-xenomai" anymore but from what I know it has "IRQPIPE". That is what I got. Change what requires to be changed, recompile linuxcnc run again and... happy days.

It took me a while to figure that one out when I was compiling mine so I save you headache.
Probably that change should be commited to git