There are configure scripts in this directory to generate the header files
used by the jemalloc library.

These scripts are named conf_<HOST_TYPE>.sh, where HOST_TYPE is one of
aarch64, arm, mips, x86, x86_64.

In order to build generate the header files for each supported HOST_TYPE,
follow these steps:

- source build/envsetup.sh
- lunch <TARGET>
- mmma -jXX bionic
- cd external/jemalloc
- autoconf
- <Modify the configure script>
- android/conf_<HOST_TYPE>.sh

Follow these instructions to modify the configure script before running
any of the conf_<HOST_TYPE>.sh scripts.

In the code that looks similar to this:

case "${host}" in
  *-*-darwin*)

Modify it to be:

case "${host}" in
  *android*)
    CFLAGS="$CFLAGS"
    CPPFLAGS="$CPPFLAGS -D_GNU_SOURCE"
    abi="elf"
    force_tls="0"
    enable_tls="0"
    $as_echo "#define JEMALLOC_HAS_ALLOCA_H 1" >>confdefs.h

    $as_echo "#define JEMALLOC_PURGE_MADVISE_DONTNEED  " >>confdefs.h

    $as_echo "#define JEMALLOC_THREADED_INIT  " >>confdefs.h
    ;;
  *-*-darwin*)