Otherwise attempts to use it on some platforms cause the following error
`error: initializer element is not a compile-time constant`
when attempting to use the corresponding `JANET_REG`.
Building janet requires janet_boot to be run on the host at build time;
- $(UNAME) can now be overridden from the make cmdline
- Added $(RUN) variable to allow a emulator to be specified
- Added ".exe" extension to binaries when using MINGW
Examples:
Cross compiling for win32 and running under wine:
```
make test \
CC=i686-w64-mingw32-gcc \
LD=i686-w64-mingw32-gcc \
UNAME=MINGW \
RUN=wine
Janet 1.27.0-ad7c3bed mingw/x86/gcc - '(doc)' for help
```
Cross compiling for aarch64 and running under qemu:
```
make repl \
CC=aarch64-none-linux-gnu-gcc \
LD=aarch64-none-linux-gnu-gcc \
RUN="qemu-aarch64 -L /tmp/aarch64/"
Janet 1.27.0-ad7c3bed linux/aarch64/gcc - '(doc)' for help
```
By take and releasing locks twice per channel in the case where nothing
is reading, there was an opportunity for ev/select to hang in the
multithreaded case. Also silence valgrind/helgrind errors.
Like getcstring, but operates on a byteview.
When writing bindings (i.e what capi.c is primarily used for), it's
common to want to accept a buffer *or* a string rather than just
a string.
For this, a byteview is perfect (and why not accept keywords while
you're at it?).
However, there's no built-in function for getting a cstring out of
a byteview, this adds one.
This also reformulates getcstring to be an edge-case of getcbytes
(simply adding an explicit check for stringness).
This turns splices that are ignored into compiler errors. Other
alternatives here should also be considered, for example making this
a compiler warning rather than an error. For example, the latest
spork as of a3ee63c137ee3234987dbbca71b566994ff8ae8c has an error of this
kind, but the resulting program does work correctly.
Also disallow splice propagation - code of the
form (+ 1 (do ;[2 3 4]) 5).
These now have semantic menaings that are pretty difficult to
work around. Code that tries to maniuplate user8 and user9 signals
right now may be affected
