+ compile the sysconst unit for wasm32-wasi

+ started working on the SysUtils unit for the WASI platform

+ enabled compilation of unit SysUtils for the WASI target. Note that WASI
snapshot building fails, when compiler is built with -CR, because of a
use-after-free bug in the compiler, related to generics. A fix for this bug
is currently being worked on.

+ enabled compilation of unit sortbase for the WASI target

+ enabled compilation of unit math for the WASI target

+ enable compilation of unit rtlconsts for the WASI target

+ enabled compilation of unit types for the WASI target

+ enabled compilation of unit typinfo for the WASI target

+ enabled compilation of unit fgl for the WASI target

+ enabled compilation of unit macpas for the WASI target

+ enabled compilation of unit iso7185 for the WASI target

+ enabled compilation of unit getopts for the WASI target

+ enabled compilation of unit charset for the WASI target

+ enabled compilation of unit cpall for the WASI target

+ enabled compilation of unit character for the WASI target

+ enabled compilation of units unicodedata and unicodenumtable for the WASI target
* fixed the dependencies of unit character

+ enabled compilation of unit fpwidestring for the WASI target

+ added classes unit for the WASI target (not yet enabled in the makefiles)

+ added tthread.inc rtl include file for WASI

+ enabled compilation of unit classes for the WASI target

+ enabled compilation of unit uuchar for the WASI platform

+ compile the unit dos (OS-specific functions are dummies for now) for the WASI target

+ enabled compilation of unit extpas for the WASI target

+ enabled the fcl-xml package for the WASI target

+ enabled the fcl-sound package for the WASI target

+ enabled the regexpr package for the WASI target

* enumerate preopened dirs on startup and store them in a list, accessible via global vars in the system unit

+ initial implementation of GetDir() for WASI

+ keep also the fds for the current dirs

+ initial implementation of resolving relative paths

+ implemented MkDir for the WASI target

+ implemented RmDir for the WASI target

+ implemented Erase() for the WASI target

+ implemented do_truncate for the WASI target

+ implemented Do_FilePos for the WASI target

+ implemented Do_FileSize for the WASI target

+ implemented Do_Seek and Do_Seekend for the WASI target

+ implemented Do_Rename for the WASI target

+ also resolve absolute paths in ConvertToFdRelativePath

+ initial WASI implementation of DOS.GetFTime. Not working yet, due to a
compiler bug, related to the import of fd_filestat_get from the wasiapi unit.

* also set doserror to 5 for access denied in dos.getfattr

+ request the FD_FILESTAT_GET capability when opening files

* fixed date calculation in WasiDateToDT

+ workaround for newer wasmtime versions that don't report the fd type of
stdin/stdout/stderr. Always assume handles 0..2 are a device, so that
standard input and output are flushed.

+ request fd_seek and fd_tell rights when opening a file

+ request the rights to set size (truncate) and set times, when a file is opened for writing

+ request fd_allocate rights when opening a file for writing

* changed the formatting of the setting of fs_rights_base in Do_Open. No functional changes.

+ request FD_DATASYNC and FD_SYNC rights when a file is opened for writing

+ always request FD_FDSTAT_SET_FLAGS rights

+ always request FD_ADVISE rights, when opening a file

+ always request pollfd_readwrite rights, when opening a file

+ implemented Randomize

+ implemented environment variables support in the DOS unit for the WASI target

* set EXEEXT to .wasm for the WASI target in fpcmake

+ started working on DOS.FindFirst

+ initial working implementation of FindFirst/FindNext

* use -1 instead of 0 for indicating empty DirFD

+ enabled compilation of unit heaptrc for the WASI target

- removed commented out code from the WASI startup code

+ added unhandled exception handling code for the branchful exceptions mode

+ implemented GetMsCount in the DOS unit for WASI

Disable utils for wasi target, because paszlib cannot be compiled due to use of goto labels

* fixed range check error in HasDriveLetter when path is 1 character long

+ define USE_NOTHREADMANAGER in the WASI system unit

Unicode' unicodenumtable.pas removed : update Makefile.fpc.

Regenerate Makefile's with trunk fpcmake

* Export wasiAlloc and wasiFree

* patch from Pierre for working around the exitcode <= 125 limitation in wasmtime

+ added unit WebAssembly for WebAssembly-specific stuff. Currently contains
the AtomicFence intrinsic, which emits the atomic.fence instruction.

Add implicit units to wasi rtl

Regenerate Makefile after: Add implicit units to wasi rtl

+ added AtomicStore() to the WebAssembly unit

* Export wasiAlloc, wasiFree

* anonymous method overloads for synchronize/queue.

* fix missing ifdef for the non win32/64/unix targets.
* also do watcom.

* refactored duplicated code for epoch to datetime and vice versa conversion
between the dos and sysutils units for the WASI platform

+ setup a thread manager (functions are still not yet implemented), when the WASI RTL is compiled with multithreading support

+ added promising _start and _initialize exports