Set rallocobj with configure, not cpp.

Set rallocobj with configure, not cpp.

* configure.in (REL_ALLOC): Unset on gnu, gnu-linux if DOUG_LEA_MALLOC.
(RALLOC_OBJ): New output variable.
* config.bat (RALLOC_OBJ): Edit to empty if sys_malloc.

* src/Makefile.in (RALLOC_OBJ): New, set by configure.
(rallocobj): Replace with the previous variable.
(otherobj): Use $RALLOC_OBJ.

* src/s/gnu.h (REL_ALLOC) [DOUG_LEA_MALLOC]:
* src/s/gnu-linux.h (REL_ALLOC) [DOUG_LEA_MALLOC]: Move undef to configure.

* msdos/sed1v2.inp (RALLOC_OBJ): Edit to ralloc.o.