libs/posix: Fix printf handling for %F format.

Before this patch, calling functions in the `printf` family and
passing %F in the format string, such as

printf("%6.2F\n", 580.0f);

would incorrectly output numbers in the exponential format:

5.8D+02

This patch fixes the output for this situation:

580.00

and fixes the behavior for programs that use %F, such as
several tests for the `fish` shell.

Change-Id: I124a5a7b93b5f551fa190501a5778726812d347c
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5424
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

libroot: Avoid glibc-internal math function usage in printf.

There's no reason for this, and we'd like to not export
these functions anymore (under non-x86/x86_64), so just use
the public macros.

glibc: Remove a ++ that was accidentally added.

Thanks to PulkoMandy for noticing!

Work towards bug #10396

glibc: Remove nested function.

Nested functions are a (again, broken) GNU extension which is not
supported by Clang. It has been replaced by a bunch of gotos and a
variable that works as a return address.

Renamed src/kernel to src/system.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@12359 a95241bf-73f2-0310-859d-f6bbb57e9c96

glibc: Remove a ++ that was accidentally added.

Thanks to PulkoMandy for noticing!

Work towards bug #10396

glibc: Remove nested function.

Nested functions are a (again, broken) GNU extension which is not
supported by Clang. It has been replaced by a bunch of gotos and a
variable that works as a return address.

Renamed src/kernel to src/system.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@12359 a95241bf-73f2-0310-859d-f6bbb57e9c96