Problems with alloca.c on Cray Y-MP EL

[Matthias Habl]

I'm trying to build/port the Emacs 21.3 on a Cray Y-MP EL (Cray-1
architecture). The program movemail needs alloca.o (the function
alloca doesn't exist on UNICOS 9.0). But alloca.c is compiled with
-Demacs according to lib-src/Makefile.in. Due to the lines

#ifdef emacs
#include "lisp.h"
#include "blockinput.h"
#endif

#ifdef emacs
    UNBLOCK_INPUT;
#endif

in lib-src/alloca.c the preprocesser expands UNBLOCK_INPUT to code
(defined in blockinput.h) which uses 'int interrupt_input_pending'.
But this variable is only defined in src/keyboard.c. So when linking
movemail the loader complains about this undefined variable.

I think that the option '-Demacs' in lib-src/Makefile.in should
be removed - independently of the operating system.

Matthias.