Snow-Chibi is a local package manager, not a system one. It can install
Scheme packages into system but they are not managed by system package
manager like dpkg, RPM, pacman, ports, etc.
Traditionally (and in accordance with Filesystem Hierarchy Standard),
/usr/local hierarchy should be used for local administrator installs --
and that's what Snow-Chibi provides.
Let's make sure that Snow-Chibi installs snowballs into /usr/local
hierarchy even if Chibi is compiled for installation into the system,
with PREFIX=/usr. Introduce a distinct bunch of variables holding paths
to library installation directories, with "SNOW" prefix:
- SNOWPREFIX - default prefix for Snow-installed stuff
- SNOWLIBDIR - custom libraries required for Snow itself
- SNOWSOLIBDIR - shared libraries required for Snow itself
- SNOWMODDIR - Snow installs Scheme modules here
- SNOWBINMODDIR - Snow installs native libraries here
All of these are set to /use/local by default, just as they are now.
However, they are not affected by regular PREFIX, LIBDIR, MODDIR, etc.
which affect only libraries bundled with Chibi.
And in order for these to work, they need to be added into the current
module path so that they can be used in parallel with system libraries.
Furthermore, we need to tweak "get-install-library-dir" function to use
those paths instead of hardcoded "/usr/local/lib" by default. Introduce
a new helper "get-install-library-dirs", similar to "get-install-dirs".
It will look up the correct installation directories in current module
path, giving preference to the ones with "/lib" in them.
With these defaults, Snow will install Scheme modules into
/usr/local/share/snow and native libraries go into /usr/local/lib/snow,
similar to how built-it libraries are installed into
/usr/local/share/chibi and /usr/local/lib/chibi is used for native code.
Of course, this can be overriden at build time by setting SNOWPREFIX or
individual SNOWMODDIR, SNOWBINMODDIR variables.
`ALLOW_MEMORY_GROWTH=1` allows to grow the wasm vm memory space as
needed and avoid out-of-memory issues. This is for development
purpose, production build will want to set memory size to something
that is fit the application (I don't remember the actual option name,
but removing ALLOW_MEMORY_GROWTH=1 from the compilation, and
re-running the app will display the good option to use).
Using read/write/exec causes an error (or possibly abort) on systems
with W^X policies (like OpenBSD and NetBSD have by default).
Since the heap does not need to be executable, just use read/write.
When mmap fails it returns MAP_FAILED, not NULL. POSIX does not
define the value for MAP_FAILED, but on at least the BSDs and Linux
its value is ((void *) -1).
Use find instead of any so load-mime-types will get the filename
instead of #t when a mime.types file is found. Otherwise an error
occurs in load-mime-types.
