undefined reference to `__mmap2' in mmap.c

When building, all the files get compiled (of course with some tweaking). But, the linker gives this error:

./obj/local/arm64-v8a/libexploit.a(mmap.o): In function `mmap':
/root/Dev/android_run_root_shell/libexploit/mmap.c:55: undefined reference to `__mmap2'
clang++: error: linker command failed with exit code 1 (use -v to see invocation)

[dadreamer]

Well, I ran into this today also. It seems that the recent NDK packages already have mmap definition. So do the following:

1. comment this line:
   extern void* __mmap2(void*, size_t, int, int, int, size_t);
2. rename mmap func in mmap.c to something, say, mmap_tmp;
3. change __mmap2 to mmap2 in the func's body.
   Or you might comment the whole func. It's allowed 'cause the exploit would stick to native mmap instead of custom one.

That's not the last error there so get ready to fix the things after. ;)