Avoid a conflict with c++ std header file on at least one platform.
Build log prior:
In file included from DKA100:[DEVEL.nethack-37.sys.share]cppregex.cpp;1:12:
In file included from /SYS$COMMON/VSICXX$LIB/INCLUDE/LIB_CXX/INCLUDE/regex:768:
In file included from /SYS$COMMON/VSICXX$LIB/INCLUDE/LIB_CXX/INCLUDE/stdexcept:5
1:
In file included from /SYS$COMMON/VSICXX$LIB/INCLUDE/LIB_CXX/INCLUDE/exception:8
7:
In file included from /SYS$COMMON/VSICXX$LIB/INCLUDE/LIB_CXX/INCLUDE/cstdlib:91:
In file included from /SYS$COMMON/VSICXX$LIB/INCLUDE/LIB_CXX/INCLUDE/stdlib.h:10
3:
/SYS$COMMON/VSICXX$LIB/INCLUDE/DECC$RTLDEF/stdlib.h:200:24: error: too many argu
ments provided to function-like macro invocation
void abort (void);
^
../INCLUDE/vmsconf.h:307:9: note: macro 'abort' defined here
#define abort() vms_abort() /* vmsmisc.c */
^
c891066bf1