The intent is to allow compilation with `-Wundef', which in turn should
make it easier to catch erroneous uses of nonexistent macros.
* libguile/__scm.h: Don't assume `BUILDING_LIBGUILE' is defined.
* libguile/conv-uinteger.i.c (SCM_TO_TYPE_PROTO): Remove unneeded CPP
conditional on `TYPE_MIN == 0'.
* libguile/fports.c: Check for the definition of `HAVE_CHSIZE' and
`HAVE_FTRUNCATE', not for their value.
* libguile/ports.c: Likewise.
* libguile/numbers.c (guile_ieee_init): Likewise with `HAVE_DINFINITY'
and `HAVE_DQNAN'.
* test-suite/standalone/test-conversion.c (ieee_init): Likewise.
* libguile/strings.c: Likewise with `SCM_STRING_LENGTH_HISTOGRAM'.
* libguile/strings.h: Likewise.
* libguile/tags.h: Likewise with `HAVE_INTTYPES_H' and `HAVE_STDINT_H'.
* libguile/threads.c: Likewise with `HAVE_PTHREAD_GET_STACKADDR_NP'.
* libguile/vm-engine.c (VM_NAME): Likewise with `VM_CHECK_IP'.
* libguile/gen-scmconfig.c (main): Use "#ifdef HAVE_", not "#if HAVE_".
* libguile/socket.c (scm_setsockopt): Likewise.
* test-suite/standalone/test-conversion.c (ieee_init): New function.
(guile_Inf, guile_NaN): New variables.
(test_from_double, test_to_double): Use them. Divisions by zero made
`cc' on Tru64 5.1b ("Compaq C V6.5-011") bail out and led to a
floating point exception when compiled with GCC on the same platform.
(main): Call `ieee_init ()'.
* test-suite/standalone/test-conversion.c: Remove extraneous semicolon
following `DEF[SU]TST' invocations since that made Compaq C
V6.5-011 (`cc' on Tru64 5.1b) bail out.
