ecvt, fcvt, gcvt, *printf, strtof, strtod, strtold act per ieee
1003.1.  after these massive changes, remove unused files which
would not work now.  reported by Maksymilian Arciemowicz;  ok theo

ok ian@, millert@

to u_int32_t to do integer math with (in a situation where that is legit)
ok otto millert

Someone may have passed a read-only string to putenv() (I'm looking
at you cron!).

standard explicitly disallows passing setenv a name with a '=' in
it but historic BSD behavior is to allow this but to ignore the '='
and anything after it.

-DSHA256_ONLY in order to save space; ok deraadt@

argument if the argument is deemed to be optional ('::').
feedback and ok jmc@ and millert@

PAGE_(SIZE|SHIFT|MASK) defines that evaluate to variables on the
sparc architecture;
ok otto@ tested on my reanimated ss20

on sparc, it expands to something that just plain does not work,
because the page size can be variable.  Sorry we didn't spot this
before.  Backing it all out to allow sparc to build; please find a
different way to fix it.

(MALLOC_OPTIONS=L). It was too slow to turn on by default, and we
don't do optional security.
requested by deraadt@ grumbling ok otto@

Move all runtime options into a structure that is made read-only
(via mprotect) after initialisation to protect against attacks that
overwrite options to turn off malloc protections (e.g. use-after-free)
Allocate the main bookkeeping data (struct dir_info) using mmap(),
thereby giving it an unpredictable address. Place a PROT_NONE guard
page on either side to further frustrate attacks on it.
Add a new 'L' option that maps struct dir_info PROT_NONE except when
in the allocator code itself. Makes attacks on it basically impossible.
feedback tedu deraadt otto canacar
ok otto

as static const

the page as possible (i.e. make malloc option P a default).
ok art@ millert@ krw@

a page to 0. P default will be changed in a separate commit.
ok millert@ art@ krw@

a separate symbolic constant for the leeway we allow when moving
allocations towards the end of a page. No functional change.

(might catch errors closer to the trouble spot) and junk fill pages just
before reuse instead of immediate (we can't access the page anyway)
since we set PROT_NONE in the F case. ok djm@

ok jmc@

tried and how many actually succeeded.

threaded case) but much smaller working set; prompted by and ok deraadt@

non-syscalls, there's just too much code not doing the right thing on
error paths; prompted by and ok deraadt@

kurt@

mapping the region next to the existing one first; there's a pretty
high chance there's a hole there we can use; ok deraadt@ tedu@

too much pressure on the amaps. ok tedu@ deraadt@

from Thomas Pfaff.  ok millert@

from Loic Tortay via jmc@

- provide proper dtoa locks
- use the real strtof implementation
- add strtold, __hdtoa, __hldtoa
- add %a/%A support
- don't lose precision in printf, don't round to double anymore
- implement extended-precision versions of libc functions: fpclassify,
isnan, isinf, signbit, isnormal, isfinite, now that the ieee.h is
fixed
- separate vax versions of strtof, and __hdtoa
- add complex math support.  added functions: cacos, casin, catan,
ccos, csin, ctan, cacosh, casinh, catanh, ccosh, csinh, ctanh, cexp,
clog, cabs, cpow, csqrt, carg, cimag, conj, cproj, creal, cacosf,
casinf, catanf, ccosf, csinf, ctanf, cacoshf, casinhf, catanhf,
ccoshf, csinhf, ctanhf, cexpf, clogf, cabsf, cpowf, csqrtf, cargf,
cimagf, conjf, cprojf, crealf
- add fdim, fmax, fmin
- add log2. (adapted implementation e_log.c.  could be more acruate
& faster, but it's good enough for now)
- remove wrappers & cruft in libm, supposed to work-around mistakes
in SVID, etc.;  use ieee versions.  fixes issues in python 2.6 for
djm@
- make _digittoint static
- proper definitions for i386, and amd64 in ieee.h
- sh, powerpc don't really have extended-precision
- add missing definitions for mips64 (quad), m{6,8}k (96-bit) float.h
for LDBL_*
- merge lead to frac for m{6,8}k, for gdtoa to work properly
- add FRAC*BITS & EXT_TO_ARRAY32 definitions in ieee.h, for hdtoa&ldtoa
to use
- add EXT_IMPLICIT_NBIT definition, which indicates implicit
normalization bit
- add regression tests for libc: fpclassify and printf
- arith.h & gd_qnan.h definitions
- update ieee.h: hppa doesn't have quad-precision, hppa64 does
- add missing prototypes to gdtoaimp
- on 64-bit platforms make sure gdtoa doesn't use a long when it
really wants an int
- etc., what i may have forgotten...
- bump libm major, due to removed&changed symbols
- no libc bump, since this is riding on djm's libc major crank from
a day ago
discussed with / requested by / testing theo, sthen@, djm@, jsg@,
merdely@, jsing@, tedu@, brad@, jakemsr@, and others.
looks good to millert@
parts of the diff ok kettenis@
this commit does not include:
- man page changes

forthcoming OpenSSL update.
Function names lose their underscore (SHA256_Init => SHA256Init) and
the various SHA256_CTX, SHA512_CTX are merged into a single SHA2_CTX
that is used for all these hashes.
ok millert@ manpage bits jmc@ "please commit" deraadt@

effort as possible in most cases; ok djm@

slightly kludgey solution for until otto fixes it properly; ok otto@

the freshly mmaped pages disrupting their pure zeroness;
ok otto@ deraadt@

rather than a pointer to the terminating nul; ok deraadt@

case spotted by beck, one by me; ok deraadt@ beck@

returns zero filled pages; remember to replace this function as well if you
provide your own malloc implementation; ok djm@ deraadt@

to defeat gcc optimization bugs. Similar to what had been done on sparc64
in the past.
ok millert@ deraadt@