Node:External Bugs, Next:Incompatibilities, Previous:Interoperation, Up:Trouble

### Problems Compiling Certain Programs

Certain programs have problems compiling.

- Parse errors may occur compiling X11 on a Decstation running Ultrix 4.2 because of problems in DEC's versions of the X11 header files `X11/Xlib.h` and `X11/Xutil.h`. People recommend adding `-I/usr/include/mit` to use the MIT versions of the header files, or fixing the header files by adding this:

                #ifdef __STDC__
                #define NeedFunctionPrototypes 0
                #endif

- On various 386 Unix systems derived from System V, including SCO, ISC, and ESIX, you may get error messages about running out of virtual memory while compiling certain programs.

  You can prevent this problem by linking GCC with the GNU malloc (which thus replaces the malloc that comes with the system). GNU malloc is available as a separate package, and also in the file `src/gmalloc.c` in the GNU Emacs 19 distribution.

  If you have installed GNU malloc as a separate library package, use this option when you relink GCC:

                MALLOC=/usr/local/lib/libgmalloc.a

  Alternatively, if you have compiled `gmalloc.c` from Emacs 19, copy the object file to `gmalloc.o` and use this option when you relink GCC:

                MALLOC=gmalloc.o