path: root/rts/rts.cabal.in

cabal-version: 3.0
name: rts
version: 1.0.2
license: BSD-3-Clause
maintainer: glasgow-haskell-users@haskell.org
build-type: Simple
flag libm
  default: @CabalHaveLibm@
flag librt
  default: @CabalHaveLibrt@
flag libdl
  default: @CabalHaveLibdl@
flag ffi
  default: @CabalHaveLibffi@
flag use-system-libffi
  default: @CabalUseSystemLibFFI@
flag libffi-adjustors
  default: @CabalLibffiAdjustors@
flag need-pthread
  default: @CabalNeedLibpthread@
flag libbfd
  default: @CabalHaveLibbfd@
flag mingwex
  default: @CabalMingwex@
flag libdw
  default: @CabalHaveLibdw@
flag libnuma
  default: @CabalHaveLibNuma@
flag 64bit
  default: @Cabal64bit@
flag leading-underscore
  default: @CabalLeadingUnderscore@
flag smp
  default: True
flag find-ptr
  default: False
-- Some cabal flags used to control the flavours we want to produce
-- for libHSrts in hadrian. By default, we just produce vanilla and
-- threaded. The flags "compose": if you enable debug and profiling,
-- you will produce vanilla, _thr, _debug, _p but also _thr_p,
-- _thr_debug_p and so on.
flag profiling
  default: False
flag debug
  default: False
flag logging
  default: False
flag dynamic
  default: False
flag thread-sanitizer
  description:
    Enable checking for data races using the ThreadSanitizer (TSAN)
    mechanism supported by GCC and Clang. See Note [ThreadSanitizer]
    in @includes/rts/TSANUtils.h@.
  default: False

library
    -- rts is a wired in package and
    -- expects the unit-id to be
    -- set without version
    ghc-options: -this-unit-id rts

    -- If we are using an in-tree libffi then we must declare it as a bundled
    -- library to ensure that Cabal installs it.
    if !flag(use-system-libffi)
      if os(windows)
        extra-bundled-libraries: Cffi-6
      else
        extra-bundled-libraries: Cffi

    -- The make build system does something special in config.mk.in
    -- for generating profiled, debugged, etc builds of those
    -- libraries, but we need to be transparent for hadrian which
    -- gets information about the rts "package" through Cabal and
    -- this cabal file. We therefore declare several
    -- flavours to be available when passing the suitable (combination of)
    -- flag(s) when configuring the RTS from hadrian, using Cabal.
    extra-library-flavours: _thr

    if flag(profiling)
      extra-library-flavours: _p _thr_p
      if flag(debug)
        extra-library-flavours: _debug_p _thr_debug_p
    if flag(debug)
      extra-library-flavours: _debug _thr_debug
      if flag(dynamic)
        extra-dynamic-library-flavours: _debug _thr_debug
    if flag(logging)
      extra-library-flavours: _l _thr_l
      if flag(dynamic)
        extra-dynamic-library-flavours: _l _thr_l
    if flag(dynamic)
      extra-dynamic-library-flavours: _thr

    if flag(thread-sanitizer)
      cc-options: -fsanitize=thread
      ld-options: -fsanitize=thread
      extra-libraries: tsan

    exposed: True
    exposed-modules:
    if flag(libm)
       -- for ldexp()
       extra-libraries: m
    if flag(librt)
       extra-libraries: rt
    if flag(libdl)
       extra-libraries: dl
    if flag(ffi)
       extra-libraries: ffi
    if os(windows)
       extra-libraries:
          -- for the linker
          wsock32 gdi32 winmm
          -- for crash dump
          dbghelp
          -- for process information
          psapi
       -- TODO: Hadrian will use this cabal file, so drop WINVER from Hadrian's configs.
       -- Minimum supported Windows version.
       -- These numbers can be found at:
       --  https://msdn.microsoft.com/en-us/library/windows/desktop/aa383745(v=vs.85).aspx
       -- If we're compiling on windows, enforce that we only support Windows 7+
       -- Adding this here means it doesn't have to be done in individual .c files
       -- and also centralizes the versioning.
       cpp-options: -D_WIN32_WINNT=0x06010000
       cc-options: -D_WIN32_WINNT=0x06010000
    if flag(need-pthread)
       -- for pthread_getthreadid_np, pthread_create, ...
       extra-libraries: pthread
    if flag(libbfd)
       -- for debugging
       extra-libraries: bfd iberty
    if flag(mingwex)
       extra-libraries: mingwex
    if flag(libdw)
       -- for backtraces
       extra-libraries: elf dw
    if flag(libnuma)
       extra-libraries: numa
    if !flag(smp)
       cpp-options: -DNOSMP

    include-dirs: build ../includes includes
                  includes/dist-derivedconstants/header @FFIIncludeDir@
                  @LibdwIncludeDir@
    includes: Stg.h
    install-includes: Cmm.h HsFFI.h MachDeps.h Rts.h RtsAPI.h Stg.h
                      ghcautoconf.h ghcconfig.h ghcplatform.h ghcversion.h
                      -- ^ from ../includes
                      DerivedConstants.h ffi.h ffitarget.h
                      -- ^ generated
                      rts/Adjustor.h
                      rts/ExecPage.h
                      rts/BlockSignals.h
                      rts/Bytecodes.h
                      rts/Config.h
                      rts/Constants.h
                      rts/EventLogFormat.h
                      rts/EventLogWriter.h
                      rts/FileLock.h
                      rts/Flags.h
                      rts/ForeignExports.h
                      rts/GetTime.h
                      rts/Globals.h
                      rts/Hpc.h
                      rts/IOInterface.h
                      rts/Libdw.h
                      rts/LibdwPool.h
                      rts/Linker.h
                      rts/Main.h
                      rts/Messages.h
                      rts/NonMoving.h
                      rts/OSThreads.h
                      rts/Parallel.h
                      rts/PrimFloat.h
                      rts/Profiling.h
                      rts/IPE.h
                      rts/Signals.h
                      rts/SpinLock.h
                      rts/StableName.h
                      rts/StablePtr.h
                      rts/StaticPtrTable.h
                      rts/TTY.h
                      rts/Threads.h
                      rts/Ticky.h
                      rts/Time.h
                      rts/Timer.h
                      rts/TSANUtils.h
                      rts/Types.h
                      rts/Utils.h
                      rts/prof/CCS.h
                      rts/prof/Heap.h
                      rts/prof/LDV.h
                      rts/storage/Block.h
                      rts/storage/ClosureMacros.h
                      rts/storage/ClosureTypes.h
                      rts/storage/Closures.h
                      rts/storage/FunTypes.h
                      rts/storage/Heap.h
                      rts/storage/GC.h
                      rts/storage/InfoTables.h
                      rts/storage/MBlock.h
                      rts/storage/TSO.h
                      stg/DLL.h
                      stg/MachRegs.h
                      stg/MachRegsForHost.h
                      stg/MiscClosures.h
                      stg/Prim.h
                      stg/Regs.h
                      stg/SMP.h
                      stg/Ticky.h
                      stg/Types.h
    if flag(64bit)
      if flag(leading-underscore)
        ld-options:
          "-Wl,-u,_hs_atomic_add64"
          "-Wl,-u,_hs_atomic_sub64"
          "-Wl,-u,_hs_atomic_and64"
          "-Wl,-u,_hs_atomic_nand64"
          "-Wl,-u,_hs_atomic_or64"
          "-Wl,-u,_hs_atomic_xor64"
          "-Wl,-u,_hs_cmpxchg64"
          "-Wl,-u,_hs_atomicread64"
          "-Wl,-u,_hs_atomicwrite64"
      else
        ld-options:
          "-Wl,-u,hs_atomic_add64"
          "-Wl,-u,hs_atomic_sub64"
          "-Wl,-u,hs_atomic_and64"
          "-Wl,-u,hs_atomic_nand64"
          "-Wl,-u,hs_atomic_or64"
          "-Wl,-u,hs_atomic_xor64"
          "-Wl,-u,hs_cmpxchg64"
          "-Wl,-u,hs_atomicread64"
          "-Wl,-u,hs_atomicwrite64"
    if flag(leading-underscore)
      ld-options:
         "-Wl,-u,_base_GHCziTopHandler_runIO_closure"
         "-Wl,-u,_base_GHCziTopHandler_runNonIO_closure"
         "-Wl,-u,_ghczmprim_GHCziTuple_Z0T_closure"
         "-Wl,-u,_ghczmprim_GHCziTypes_True_closure"
         "-Wl,-u,_ghczmprim_GHCziTypes_False_closure"
         "-Wl,-u,_base_GHCziPack_unpackCString_closure"
         "-Wl,-u,_base_GHCziWeak_runFinalizzerBatch_closure"
         "-Wl,-u,_base_GHCziIOziException_stackOverflow_closure"
         "-Wl,-u,_base_GHCziIOziException_heapOverflow_closure"
         "-Wl,-u,_base_GHCziIOziException_allocationLimitExceeded_closure"
         "-Wl,-u,_base_GHCziIOziException_blockedIndefinitelyOnMVar_closure"
         "-Wl,-u,_base_GHCziIOziException_blockedIndefinitelyOnSTM_closure"
         "-Wl,-u,_base_GHCziIOziException_cannotCompactFunction_closure"
         "-Wl,-u,_base_GHCziIOziException_cannotCompactPinned_closure"
         "-Wl,-u,_base_GHCziIOziException_cannotCompactMutable_closure"
         "-Wl,-u,_base_GHCziIOPort_doubleReadException_closure"
         "-Wl,-u,_base_ControlziExceptionziBase_nonTermination_closure"
         "-Wl,-u,_base_ControlziExceptionziBase_nestedAtomically_closure"
         "-Wl,-u,_base_GHCziEventziThread_blockedOnBadFD_closure"
         "-Wl,-u,_base_GHCziConcziSync_runSparks_closure"
         "-Wl,-u,_base_GHCziConcziIO_ensureIOManagerIsRunning_closure"
         "-Wl,-u,_base_GHCziConcziIO_interruptIOManager_closure"
         "-Wl,-u,_base_GHCziConcziIO_ioManagerCapabilitiesChanged_closure"
         "-Wl,-u,_base_GHCziConcziSignal_runHandlersPtr_closure"
         "-Wl,-u,_base_GHCziTopHandler_flushStdHandles_closure"
         "-Wl,-u,_base_GHCziTopHandler_runMainIO_closure"
         "-Wl,-u,_ghczmprim_GHCziTypes_Czh_con_info"
         "-Wl,-u,_ghczmprim_GHCziTypes_Izh_con_info"
         "-Wl,-u,_ghczmprim_GHCziTypes_Fzh_con_info"
         "-Wl,-u,_ghczmprim_GHCziTypes_Dzh_con_info"
         "-Wl,-u,_ghczmprim_GHCziTypes_Wzh_con_info"
         "-Wl,-u,_base_GHCziPtr_Ptr_con_info"
         "-Wl,-u,_base_GHCziPtr_FunPtr_con_info"
         "-Wl,-u,_base_GHCziInt_I8zh_con_info"
         "-Wl,-u,_base_GHCziInt_I16zh_con_info"
         "-Wl,-u,_base_GHCziInt_I32zh_con_info"
         "-Wl,-u,_base_GHCziInt_I64zh_con_info"
         "-Wl,-u,_base_GHCziWord_W8zh_con_info"
         "-Wl,-u,_base_GHCziWord_W16zh_con_info"
         "-Wl,-u,_base_GHCziWord_W32zh_con_info"
         "-Wl,-u,_base_GHCziWord_W64zh_con_info"
         "-Wl,-u,_base_GHCziStable_StablePtr_con_info"
         "-Wl,-u,_hs_atomic_add8"
         "-Wl,-u,_hs_atomic_add16"
         "-Wl,-u,_hs_atomic_add32"
         "-Wl,-u,_hs_atomic_sub8"
         "-Wl,-u,_hs_atomic_sub16"
         "-Wl,-u,_hs_atomic_sub32"
         "-Wl,-u,_hs_atomic_and8"
         "-Wl,-u,_hs_atomic_and16"
         "-Wl,-u,_hs_atomic_and32"
         "-Wl,-u,_hs_atomic_nand8"
         "-Wl,-u,_hs_atomic_nand16"
         "-Wl,-u,_hs_atomic_nand32"
         "-Wl,-u,_hs_atomic_or8"
         "-Wl,-u,_hs_atomic_or16"
         "-Wl,-u,_hs_atomic_or32"
         "-Wl,-u,_hs_atomic_xor8"
         "-Wl,-u,_hs_atomic_xor16"
         "-Wl,-u,_hs_atomic_xor32"
         "-Wl,-u,_hs_cmpxchg8"
         "-Wl,-u,_hs_cmpxchg16"
         "-Wl,-u,_hs_cmpxchg32"
         "-Wl,-u,_hs_xchg8"
         "-Wl,-u,_hs_xchg16"
         "-Wl,-u,_hs_xchg32"
         "-Wl,-u,_hs_xchg64"
         "-Wl,-u,_hs_atomicread8"
         "-Wl,-u,_hs_atomicread16"
         "-Wl,-u,_hs_atomicread32"
         "-Wl,-u,_hs_atomicwrite8"
         "-Wl,-u,_hs_atomicwrite16"
         "-Wl,-u,_hs_atomicwrite32"

      if flag(find-ptr)
        -- This symbol is useful in gdb, but not referred to anywhere,
        -- so we need to force it to be included in the binary.
        ld-options: "-Wl,-u,_findPtr"

    else
      ld-options:
         "-Wl,-u,base_GHCziTopHandler_runIO_closure"
         "-Wl,-u,base_GHCziTopHandler_runNonIO_closure"
         "-Wl,-u,ghczmprim_GHCziTuple_Z0T_closure"
         "-Wl,-u,ghczmprim_GHCziTypes_True_closure"
         "-Wl,-u,ghczmprim_GHCziTypes_False_closure"
         "-Wl,-u,base_GHCziPack_unpackCString_closure"
         "-Wl,-u,base_GHCziWeak_runFinalizzerBatch_closure"
         "-Wl,-u,base_GHCziIOziException_stackOverflow_closure"
         "-Wl,-u,base_GHCziIOziException_heapOverflow_closure"
         "-Wl,-u,base_GHCziIOziException_allocationLimitExceeded_closure"
         "-Wl,-u,base_GHCziIOziException_blockedIndefinitelyOnMVar_closure"
         "-Wl,-u,base_GHCziIOziException_blockedIndefinitelyOnSTM_closure"
         "-Wl,-u,base_GHCziIOziException_cannotCompactFunction_closure"
         "-Wl,-u,base_GHCziIOziException_cannotCompactPinned_closure"
         "-Wl,-u,base_GHCziIOziException_cannotCompactMutable_closure"
         "-Wl,-u,base_GHCziIOPort_doubleReadException_closure"
         "-Wl,-u,base_ControlziExceptionziBase_nonTermination_closure"
         "-Wl,-u,base_ControlziExceptionziBase_nestedAtomically_closure"
         "-Wl,-u,base_GHCziEventziThread_blockedOnBadFD_closure"
         "-Wl,-u,base_GHCziConcziSync_runSparks_closure"
         "-Wl,-u,base_GHCziConcziIO_ensureIOManagerIsRunning_closure"
         "-Wl,-u,base_GHCziConcziIO_interruptIOManager_closure"
         "-Wl,-u,base_GHCziConcziIO_ioManagerCapabilitiesChanged_closure"
         "-Wl,-u,base_GHCziConcziSignal_runHandlersPtr_closure"
         "-Wl,-u,base_GHCziTopHandler_flushStdHandles_closure"
         "-Wl,-u,base_GHCziTopHandler_runMainIO_closure"
         "-Wl,-u,ghczmprim_GHCziTypes_Czh_con_info"
         "-Wl,-u,ghczmprim_GHCziTypes_Izh_con_info"
         "-Wl,-u,ghczmprim_GHCziTypes_Fzh_con_info"
         "-Wl,-u,ghczmprim_GHCziTypes_Dzh_con_info"
         "-Wl,-u,ghczmprim_GHCziTypes_Wzh_con_info"
         "-Wl,-u,base_GHCziPtr_Ptr_con_info"
         "-Wl,-u,base_GHCziPtr_FunPtr_con_info"
         "-Wl,-u,base_GHCziInt_I8zh_con_info"
         "-Wl,-u,base_GHCziInt_I16zh_con_info"
         "-Wl,-u,base_GHCziInt_I32zh_con_info"
         "-Wl,-u,base_GHCziInt_I64zh_con_info"
         "-Wl,-u,base_GHCziWord_W8zh_con_info"
         "-Wl,-u,base_GHCziWord_W16zh_con_info"
         "-Wl,-u,base_GHCziWord_W32zh_con_info"
         "-Wl,-u,base_GHCziWord_W64zh_con_info"
         "-Wl,-u,base_GHCziStable_StablePtr_con_info"
         "-Wl,-u,hs_atomic_add8"
         "-Wl,-u,hs_atomic_add16"
         "-Wl,-u,hs_atomic_add32"
         "-Wl,-u,hs_atomic_sub8"
         "-Wl,-u,hs_atomic_sub16"
         "-Wl,-u,hs_atomic_sub32"
         "-Wl,-u,hs_atomic_and8"
         "-Wl,-u,hs_atomic_and16"
         "-Wl,-u,hs_atomic_and32"
         "-Wl,-u,hs_atomic_nand8"
         "-Wl,-u,hs_atomic_nand16"
         "-Wl,-u,hs_atomic_nand32"
         "-Wl,-u,hs_atomic_or8"
         "-Wl,-u,hs_atomic_or16"
         "-Wl,-u,hs_atomic_or32"
         "-Wl,-u,hs_atomic_xor8"
         "-Wl,-u,hs_atomic_xor16"
         "-Wl,-u,hs_atomic_xor32"
         "-Wl,-u,hs_cmpxchg8"
         "-Wl,-u,hs_cmpxchg16"
         "-Wl,-u,hs_cmpxchg32"
         "-Wl,-u,hs_xchg8"
         "-Wl,-u,hs_xchg16"
         "-Wl,-u,hs_xchg32"
         "-Wl,-u,hs_xchg64"
         "-Wl,-u,hs_atomicread8"
         "-Wl,-u,hs_atomicread16"
         "-Wl,-u,hs_atomicread32"
         "-Wl,-u,hs_atomicwrite8"
         "-Wl,-u,hs_atomicwrite16"
         "-Wl,-u,hs_atomicwrite32"

      if flag(find-ptr)
        -- This symbol is useful in gdb, but not referred to anywhere,
        -- so we need to force it to be included in the binary.
        ld-options: "-Wl,-u,findPtr"
         -- This symbol is useful in gdb, but not referred to anywhere,
         -- so we need to force it to be included in the binary.
         "-Wl,-u,findPtr"

    if os(windows)
      if flag(leading-underscore)
        ld-options:
           "-Wl,-u,_base_GHCziEventziWindows_processRemoteCompletion_closure"
      else
        ld-options:
           "-Wl,-u,base_GHCziEventziWindows_processRemoteCompletion_closure"

    if os(osx)
      ld-options: "-Wl,-search_paths_first"
                  -- See Note [fd_set_overflow]
                  "-Wl,-U,___darwin_check_fd_set_overflow"
      if !arch(x86_64) && !arch(aarch64)
         ld-options: -read_only_relocs warning

    cmm-sources: Apply.cmm
                 Compact.cmm
                 Exception.cmm
                 HeapStackCheck.cmm
                 PrimOps.cmm
                 StgMiscClosures.cmm
                 StgStartup.cmm
                 StgStdThunks.cmm
                 Updates.cmm
                 -- AutoApply is generated
                 AutoApply.cmm

    -- Adjustor stuff
    if flag(libffi-adjustors)
      c-sources: adjustor/LibffiAdjustor.c
    else
      -- Use GHC's native adjustors
      if arch(i386)
        asm-sources: AdjustorAsm.S
        c-sources: adjustor/Nativei386.c
      if arch(x86_64)
        c-sources: adjustor/NativeAmd64.c
      if arch(ppc) || arch(ppc64)
        asm-sources: AdjustorAsm.S
        c-sources: adjustor/NativePowerPC.c
      if arch(ia64)
        c-sources: adjustor/NativeIA64.c
      if arch(sparc)
        c-sources: adjustor/NativeSparc.c

    -- Use assembler STG entrypoint on archictures where it is used
    if arch(ppc) || arch(ppc64) || arch(s390x) || arch(riscv64)
      asm-sources: StgCRunAsm.S

    c-sources: Adjustor.c
               ExecPage.c
               Arena.c
               Capability.c
               CheckUnload.c
               ClosureFlags.c
               Disassembler.c
               FileLock.c
               ForeignExports.c
               Globals.c
               Hash.c
               Heap.c
               Hpc.c
               HsFFI.c
               Inlines.c
               Interpreter.c
               IOManager.c
               LdvProfile.c
               Libdw.c
               LibdwPool.c
               Linker.c
               Messages.c
               OldARMAtomic.c
               PathUtils.c
               Pool.c
               Printer.c
               ProfHeap.c
               ProfilerReport.c
               ProfilerReportJson.c
               Profiling.c
               IPE.c
               Proftimer.c
               RaiseAsync.c
               RetainerProfile.c
               RetainerSet.c
               RtsAPI.c
               RtsDllMain.c
               RtsFlags.c
               RtsMain.c
               RtsMessages.c
               RtsStartup.c
               RtsSymbolInfo.c
               RtsSymbols.c
               RtsUtils.c
               STM.c
               Schedule.c
               Sparks.c
               SpinLock.c
               StableName.c
               StablePtr.c
               StaticPtrTable.c
               Stats.c
               StgCRun.c
               StgPrimFloat.c
               Task.c
               ThreadLabels.c
               ThreadPaused.c
               Threads.c
               Ticky.c
               Timer.c
               TopHandler.c
               Trace.c
               TraverseHeap.c
               TraverseHeapTest.c
               WSDeque.c
               Weak.c
               eventlog/EventLog.c
               eventlog/EventLogWriter.c
               hooks/FlagDefaults.c
               hooks/LongGCSync.c
               hooks/MallocFail.c
               hooks/OnExit.c
               hooks/OutOfHeap.c
               hooks/StackOverflow.c
               linker/CacheFlush.c
               linker/Elf.c
               linker/LoadArchive.c
               linker/M32Alloc.c
               linker/MachO.c
               linker/macho/plt.c
               linker/macho/plt_aarch64.c
               linker/PEi386.c
               linker/SymbolExtras.c
               linker/elf_got.c
               linker/elf_plt.c
               linker/elf_plt_aarch64.c
               linker/elf_plt_arm.c
               linker/elf_reloc.c
               linker/elf_reloc_aarch64.c
               linker/elf_tlsgd.c
               linker/elf_util.c
               sm/BlockAlloc.c
               sm/CNF.c
               sm/Compact.c
               sm/Evac.c
               sm/Evac_thr.c
               sm/GC.c
               sm/GCAux.c
               sm/GCUtils.c
               sm/MBlock.c
               sm/MarkWeak.c
               sm/NonMoving.c
               sm/NonMovingCensus.c
               sm/NonMovingMark.c
               sm/NonMovingScav.c
               sm/NonMovingShortcut.c
               sm/NonMovingSweep.c
               sm/Sanity.c
               sm/Scav.c
               sm/Scav_thr.c
               sm/Storage.c
               sm/Sweep.c
               fs.c
               -- I wish we had wildcards..., this would be:
               -- *.c hooks/**/*.c sm/**/*.c eventlog/**/*.c linker/**/*.c

    extra-source-files:
               -- This file needs to be in the package but shouldn't be compiled on its own.
               xxhash.c

    if os(windows)
       c-sources: win32/AsyncMIO.c
                  win32/AsyncWinIO.c
                  win32/AwaitEvent.c
                  win32/ConsoleHandler.c
                  win32/GetEnv.c
                  win32/GetTime.c
                  win32/MIOManager.c
                  win32/OSMem.c
                  win32/OSThreads.c
                  win32/ThrIOManager.c
                  win32/Ticker.c
                  win32/WorkQueue.c
                  win32/veh_excn.c
                  -- win32/**/*.c
    else
       c-sources: posix/GetEnv.c
                  posix/GetTime.c
                  posix/Ticker.c
                  posix/OSMem.c
                  posix/OSThreads.c
                  posix/Select.c
                  posix/Signals.c
                  posix/TTY.c
                  -- ticker/*.c
                  -- We don't want to compile posix/ticker/*.c, these will be #included
                  -- from Ticker.c


-- Note [fd_set_overflow]
-- ~~~~~~~~~~~~~~~~~~~~~~
-- In this note is the very sad tale of __darwin_fd_set_overflow.
-- The 8.10.5 release was broken because it was built in an environment
-- where the libraries were provided by XCode 12.*, these libraries introduced
-- a reference to __darwin_fd_set_overflow via the FD_SET macro which is used in
-- Select.c. Unfortunately, this symbol is not available with XCode 11.* which
-- led to a linker error when trying to link anything. This is almost certainly
-- a bug in XCode but we still have to work around it.

-- Undefined symbols for architecture x86_64:
--  "___darwin_check_fd_set_overflow", referenced from:
--      _awaitEvent in libHSrts.a(Select.o)
-- ld: symbol(s) not found for architecture x86_64

-- One way to fix this is to upgrade your version of xcode, but this would
-- force the upgrade on users prematurely. Fortunately it also seems safe to pass
-- the linker option "-Wl,-U,___darwin_check_fd_set_overflow" because the usage of
-- the symbol is guarded by a guard to check if it's defined.

-- __header_always_inline int
-- __darwin_check_fd_set(int _a, const void *_b)
-- {
--    if ((uintptr_t)&__darwin_check_fd_set_overflow != (uintptr_t) 0) {
--#if defined(_DARWIN_UNLIMITED_SELECT) || defined(_DARWIN_C_SOURCE)
--        return __darwin_check_fd_set_overflow(_a, _b, 1);
--#else
--        return __darwin_check_fd_set_overflow(_a, _b, 0);
--#endif
--    } else {
--        return 1;
--    }
--}

-- Across the internet there are many other reports of this issue
--  See: https://github.com/mono/mono/issues/19393
--     , https://github.com/sitsofe/fio/commit/b6a1e63a1ff607692a3caf3c2db2c3d575ba2320

-- The issue was originally reported in #19950