Et voila...

  $ ./configure wasm-wasi-component
  configuring wasm-wasi-component module
  Looking for rust compiler ... found.
  Looking for cargo ... found.
   + wasm-wasi-component module: wasm_wasi_component.unit.so
  $ make install
  test -d /opt/unit/sbin          || install -d /opt/unit/sbin
  install -p build/sbin/unitd /opt/unit/sbin/
  test -d /opt/unit/state                 || install -d /opt/unit/state
  test -d /opt/unit               || install -d /opt/unit
  test -d /opt/unit               || install -d /opt/unit
  test -d /opt/unit/share/man/man8                || install -d /opt/unit/sh
man/man8
  install -p -m644 build/share/man/man8/unitd.8           /opt/unit/share/ma
n8/
  make build/src/nxt_unit.o
  make[1]: Entering directory '/home/andrew/src/unit'
  make[1]: 'build/src/nxt_unit.o' is up to date.
  make[1]: Leaving directory '/home/andrew/src/unit'
  cargo build --release --manifest-path src/wasm-wasi-component/Cargo.toml
      Finished release [optimized] target(s) in 0.55s
  install -d /opt/unit/modules
  install -p src/wasm-wasi-component/target/release/libwasm_wasi_component.so \
          /opt/unit/modules/wasm_wasi_component.unit.so

Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

This allows to configure the Wasm module, e.g

  ./configure wasm --include-path=/path/to/wasmtime-v11.0.0-x86_64-linux-c-api/include --lib-path=/path/to/wasmtime-v11.0.0-x86_64-linux-c-api/lib --rpath

--rpath as above says to set the rpath to the value of --lib-path. You
can alternatively specify a directory to use as the rpath. Or simply
omit the option to not have an rpath set.

This is mostly useful for during development where you may not have the
Wasmtime stuff installed to system directories or you want to test with
newer/different versions.

See ./configure wasm --help for a full list of options.

Reviewed-by: Alejandro Colomar <alx@nginx.com>
Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

Configuration and building example:

  ./configure
  ./configure python
  ./configure php
  ./configure go
  make all

or

  ./configure
  make nginext
  ./configure python
  make python
  ./configure php
  make php
  ./configure go
  make go

Modules configuration options and building examples:

  ./configure python --module=python2 --config=python2.7-config
  make python2

  ./configure php --module=php7 --config=php7.0-config
                  --lib-path=/usr/local/php7.0
  make php7

  ./configure go --go=go1.6 --go-path=${HOME}/go1.6
  make go1.6

configuration infrastructure.