Currently checking mmap support in libelf failed due to wrong flags.
CHK libelf
CHK libdw
CHK libunwind
CHK -DLIBELF_MMAP
/tmp/ccYJwdR0.o: In function `main':
:(.text+0x18): undefined reference to `elf_begin'
collect2: error: ld returned 1 exit status
This cannot happen since we checked the elf_begin() when checking
libelf and it succeeded.