Recompile with cargo and rebuild temacs when the Rust source changes

[spacecowboy]

• Moved rust compilation inside the src-Makefile
• Added a target to build the build the remacs archive. This target
  depends on all rust src files

Examples

All examples assume a previously completed run of make or make src and abbreviates some output with [...]

Updated rust source file: runs cargo and builds temacs

$ touch rust_src/src/lisp.rs
$ make src
make -C lib all
[...]
make[2]: 'libXMenu11.a' is up to date.
make[2]: Leaving directory '/home/jonas/workspace/remacs/oldXMenu'
RUSTFLAGS= \
cargo build --release --manifest-path ../rust_src/Cargo.toml
   Compiling remacs v0.1.0 (file:///home/jonas/workspace/remacs/src/../rust_src)
note: link against the following native artifacts when linking against this static library

note: the order and any duplication can be significant on some platforms, and so may need to be preserved

note: library: util

note: library: dl

note: library: pthread

note: library: gcc_s

note: library: c

note: library: m

note: library: rt

note: library: util

    Finished release [optimized] target(s) in 1.44 secs
mkdir -p ../rust_src/target/
echo "--release " > ../rust_src/target/.rustflags.tmp
diff -q ../rust_src/target/.rustflags ../rust_src/target/.rustflags.tmp || cp ../rust_src/target/.rustflags.tmp ../rust_src/target/.rustflags
rm -f ../rust_src/target/.rustflags.tmp
[...]
  CCLD     temacs
/bin/mkdir -p ../etc
make -C ../lisp update-subdirs
make[2]: Entering directory '/home/jonas/workspace/remacs/lisp'
make[2]: Leaving directory '/home/jonas/workspace/remacs/lisp'
./temacs --batch  --load loadup bootstrap
[...]
Adding name remacs-26.0.50.2
ln -f remacs bootstrap-emacs
make[1]: Leaving directory '/home/jonas/workspace/remacs/src'

Updated C source file: does NOT run cargo and builds temacs

$ touch src/lisp.h
$ make src
make -C lib all
[...]
make[2]: 'libXMenu11.a' is up to date.
make[2]: Leaving directory '/home/jonas/workspace/remacs/oldXMenu'
  CC       dispnew.o
[...]
mkdir -p ../rust_src/target/
echo "--release " > ../rust_src/target/.rustflags.tmp
diff -q ../rust_src/target/.rustflags ../rust_src/target/.rustflags.tmp || cp ../rust_src/target/.rustflags.tmp ../rust_src/target/.rustflags
rm -f ../rust_src/target/.rustflags.tmp
[...]
  CCLD     temacs
/bin/mkdir -p ../etc
make -C ../lisp update-subdirs
make[2]: Entering directory '/home/jonas/workspace/remacs/lisp'
make[2]: Leaving directory '/home/jonas/workspace/remacs/lisp'
./temacs --batch  --load loadup bootstrap
[...]
Adding name remacs-26.0.50.7
ln -f remacs bootstrap-emacs
make[1]: Leaving directory '/home/jonas/workspace/remacs/src'

[jeandudey]

See #104

[spacecowboy]

Thanks. Rebased.

[Wilfred]

Great stuff, thanks :)