Add jemalloc support

Prerequisite of !616

Test Plan

D6343:

• cmake -GNinja .. -DUSE_JEMALLOC_EXPERIMENTAL=ON -DCMAKE_C_FLAGS=-Werror

Check that you get no build failure.

D6055 / D6027:

• cmake -GNinja .. -DUSE_JEMALLOC_EXPERIMENTAL=ON

On Debian, check in the cmake output that libdl is required.

• ninja all check
• cmake -GNinja .. -DCMAKE_TOOLCHAIN_FILE=../cmake/platforms/Linux64.cmake -DUSE_JEMALLOC_EXPERIMENTAL=ON

Check in the cmake output that libdl is NOT required.

D6038: Obtain the MacOS10.14.sdk.tar.xz that as described in doc/gitian-building.md Build all dependencies:

cd depends
mkdir SDKs
tar -C SDKs -xf /path/to/MacOS10.14.sdk.tar.xz
make build-all

Check that the 'build-all' completes successfully (no error). Then cross build for all platforms with jemalloc enabled - save the following to a script file and run it in the base folder of your working area.

#!/bin/bash

for platform in Linux32 Linux64 LinuxAArch64 LinuxARM OSX Win64
do
  rm -rf build_${platform}
  mkdir build_${platform}
  cd build_${platform}
  # Need to disable seeder build on Windows
  SEEDER="" && [[ ${platform} = "Win64" ]] && SEEDER="-DBUILD_BITCOIN_SEEDER=OFF"
  cmake -GNinja .. -DCMAKE_TOOLCHAIN_FILE=../cmake/platforms/${platform}.cmake -DUSE_JEMALLOC_EXPERIMENTAL=ON ${SEEDER}
  ninja all || {
      echo "Failed to build ${platform}."
      exit 1
  }
  cd ..
done

Check that this does not exit with a failure. You'll need to collect the resulting binaries and run them on various platforms.

Gitian build: Perform a gitian build for all platforms (Linux, Win, MacOS). All builds should work. Test that the resulting binaries run.

Merge instructions: DO NOT SQUASH

Tags for admin - do not delete:

Differential Revision: https://reviews.bitcoinabc.org/D6027 Differential Revision: https://reviews.bitcoinabc.org/D6038 Differential Revision: https://reviews.bitcoinabc.org/D6055 Differential Revision: https://reviews.bitcoinabc.org/D6343