[Ecls-list] Ecl does not react on SIGINT on Linux

[Tobias C. Rittweiler]

On ECL 9.12.1, it enters the debugger if it receives SIGINT.

On current HEAD, it just ignores the signal. Consequently, C-c C-c'ing
is ignored, too, at the terminal.

Ubuntu 9.10, Linux-x86/32 2.6.31

(:ASDF :LINUX :FORMATTER :UINT64-T :UINT32-T :UINT16-T :RELATIVE-PACKAGE-NAMES
 :UNICODE :DFFI :CLOS-STREAMS :CMU-FORMAT :UNIX :ECL-PDE :DLOPEN :CLOS :THREADS
 :BOEHM-GC :ANSI-CL :COMMON-LISP :IEEE-FLOATING-POINT :PREFIXED-API :FFI
 :PENTIUM3 :COMMON :ECL)

  -T.