#
#POSIX development environment.
#Allows us to build programs that require a POSIX API.
#NOTE: The following requires 64 bit Windows.
#Should not be a problem in the year 2018.
#

if (WIN32)
#On Windows, we rely on MSYS2 to provide a toolchain which can build
#applications that rely on the POSIX API. This is done in such a way that
#the resulting applications run on Windows using the MSYS2.DLL POSIX emulation
#layer.
ExternalProject_Add (
  posix-dev
  PREFIX ${CMAKE_INSTALL_PREFIX}
  BUILD_IN_SOURCE 1
  DOWNLOAD_COMMAND ""
  SOURCE_DIR ${POSIX_ROOT}
  #To make sense of the alchemy below, see https://github.com/msys2/msys2/wiki/MSYS2-installation
  CONFIGURE_COMMAND ""
  #Update the package database and then install development tools
  #See https://github.com/Alexpux/MSYS2-packages/issues/148 for which packages we install
  BUILD_COMMAND ${CMAKE_COMMAND} -E env MSYSTEM=MSYS2 CHERE_INVOKING=1 ${POSIX_ROOT}/usr/bin/bash.exe --login -c "pacman -S --noconfirm --needed base-devel gcc"
  INSTALL_COMMAND ""
  DEPENDS posix-runtime
)
endif (WIN32)

if (UNIX)
#Define an empty posix-dev project so that dependencies on posix dev tools can
#be specified indendently of WIN32 or UNIX.
ExternalProject_Add (
  posix-dev
  BUILD_IN_SOURCE 1
  DOWNLOAD_COMMAND ""
  CONFIGURE_COMMAND ""
  BUILD_COMMAND ""
  INSTALL_COMMAND ""
  DEPENDS posix-runtime
)
endif (UNIX)