ide-backend-server crashes for some orderings of adding C files

[mgsloan]

There are some test suite failures related to C files. This seems to be related to the old, resolved bugs #228 / #230. The symptoms are similar - ide-backend-server is dieing.

I'm not sure how to diagnose / resolve this. Creating this ticket to track fixing the issue and reinstating the tests.

[mgsloan]

Log of the failures:

    Using C files
      Basic functionality, recompiling Haskell modules when necessary:                                      FAIL (16.72s)
        expected: RunOk
         but got: RunGhcException "External exception: Server killed. Local exception: user error (IdeSession.RPC.Stream ended, causing demandInput: not enough bytes)"
      C files in subdirs:                                                                                   OK (9.84s)
      Errors and warnings in the C code:                                                                    OK (4.43s)
      Errors in C file, then update C file (#201):                                                          OK (3.42s)
      C header files in subdirectories (#212):                                                              OK (2.08s)
      C code writes to stdout (#210):                                                                       OK (1.50s)
      Deleting C file should unload object file (#241):                                                     FAIL (3.12s)
        expected: RunOk
         but got: RunGhcException "External exception: Server killed. Local exception: user error (IdeSession.RPC.Stream ended, causing demandInput: not enough bytes)"
      Two C files (no cyclic dependencies)
        [Load a.c]; [Load b.c]; [Load .hs]:                                                                 OK (4.10s)
        [Load b.c]; [Load a.c]; [Load .hs]:                                                                 OK (4.54s)
        [Load b.c]; [Load .hs]; [Load a.c]:                                                                 FAIL (2.95s)
          expected: RunGhcException "External exception: Server killed. Local exception: user error (IdeSession.RPC.Stream ended, causing demandInput: not enough bytes)"
           but got: RunOk
        [Load a.c]; [Load .hs]; [Load b.c]:                                                                 OK (2.87s)
        [Load .hs]; [Load a.c]; [Load b.c]:                                                                 OK (3.90s)
        [Load .hs]; [Load b.c]; [Load a.c]:                                                                 FAIL (3.16s)
          expected: RunGhcException "External exception: Server killed. Local exception: user error (IdeSession.RPC.Stream ended, causing demandInput: not enough bytes)"
           but got: RunOk
        [Load a.c]; [Load b.c, Load .hs]:                                                                   OK (2.95s)
        [Load b.c, Load .hs]; [Load a.c]:                                                                   FAIL (2.65s)
          expected: RunGhcException "External exception: Server killed. Local exception: user error (IdeSession.RPC.Stream ended, causing demandInput: not enough bytes)"
           but got: RunOk
        [Load a.c, Load b.c]; [Load .hs]:                                                                   OK (2.58s)
        [Load b.c]; [Load a.c, Load .hs]:                                                                   OK (2.07s)
        [Load a.c, Load .hs]; [Load b.c]:                                                                   OK (2.31s)
        [Load .hs]; [Load a.c, Load b.c]:                                                                   OK (1.96s)
        [Load a.c, Load b.c, Load .hs]:                                                                     OK (2.20s)
      Two C files (C files mutually dependent)
        [Load a.c]; [Load b.c]; [Load .hs]:                                                                 OK (3.26s)
        [Load b.c]; [Load a.c]; [Load .hs]:                                                                 OK (1.84s)
        [Load b.c]; [Load .hs]; [Load a.c]:                                                                 FAIL (2.72s)
          expected: RunGhcException "External exception: Server killed. Local exception: user error (IdeSession.RPC.Stream ended, causing demandInput: not enough bytes)"
           but got: RunOk
        [Load a.c]; [Load .hs]; [Load b.c]:                                                                 OK (2.56s)
        [Load .hs]; [Load a.c]; [Load b.c]:                                                                 OK (3.82s)
        [Load .hs]; [Load b.c]; [Load a.c]:                                                                 FAIL (3.59s)
          expected: RunGhcException "External exception: Server killed. Local exception: user error (IdeSession.RPC.Stream ended, causing demandInput: not enough bytes)"
           but got: RunOk
        [Load a.c]; [Load b.c, Load .hs]:                                                                   OK (2.74s)
        [Load b.c, Load .hs]; [Load a.c]:                                                                   FAIL (2.43s)
          expected: RunGhcException "External exception: Server killed. Local exception: user error (IdeSession.RPC.Stream ended, causing demandInput: not enough bytes)"
           but got: RunOk
        [Load a.c, Load b.c]; [Load .hs]:                                                                   OK (4.32s)
        [Load b.c]; [Load a.c, Load .hs]:                                                                   OK (2.99s)
        [Load a.c, Load .hs]; [Load b.c]:                                                                   OK (2.94s)
        [Load .hs]; [Load a.c, Load b.c]:                                                                   OK (3.16s)
        [Load a.c, Load b.c, Load .hs]:                                                                     OK (2.69s)