Compile issues under DragonflyBSD
**Describe the bug**
Compile issues under DragonflyBSD

**To Reproduce**
Cmake options, both:

`cmake .. -DXMRIG_DEPS=scripts/deps -DBUILD_STATIC=ON -DCMAKE_C_COMPILER=clang
`

AND

`cmake .. -DXMRIG_DEPS=scripts/deps -DBUILD_STATIC=ON
`

Results:

```
[ 75%] Building CXX object CMakeFiles/xmrig.dir/src/crypto/cn/CnCtx.cpp.o
[...]/xmrig/src/crypto/common/VirtualMemory_unix.cpp:154:109: error: use of undeclared identifier 'MAP_POPULATE'
        mem = mmap(0, align(size), PROT_READ | PROT_WRITE | SECURE_PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE | hugePagesFlag(hugePageSize()), -1, 0);
                                                                                                            ^
/root/gits/xmrig/src/crypto/common/VirtualMemory_unix.cpp:174:85: error: use of undeclared identifier 'MAP_HUGETLB'
    void *mem = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB | MAP_POPULATE | hugePagesFlag(hugePageSize()), 0, 0);
                                                                                    ^
/root/gits/xmrig/src/crypto/common/VirtualMemory_unix.cpp:174:99: error: use of undeclared identifier 'MAP_POPULATE'
    void *mem = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB | MAP_POPULATE | hugePagesFlag(hugePageSize()), 0, 0);
                                                                                                  ^
[ 75%] Building CXX object CMakeFiles/xmrig.dir/src/crypto/cn/CnHash.cpp.o
[ 76%] Building CXX object CMakeFiles/xmrig.dir/src/crypto/common/HugePagesInfo.cpp.o
3 errors generated.
--- CMakeFiles/xmrig.dir/src/crypto/common/VirtualMemory_unix.cpp.o ---
*** [CMakeFiles/xmrig.dir/src/crypto/common/VirtualMemory_unix.cpp.o] Error code 1
```

**Expected behavior**
Compile without errors

**Required data**
 - OS: Dragonfly BSD

**Additional context**
N/A
