[nix] add 'dev-mode' into nix

It is incovenient for users to always input strings like
".#t1.blastoise.ip.cases.mlir.hello.emu-result". So here is an env to
help improve the current situation. With the "dev-mode" shell, users
will have many bash function to help them set the current development "mode".

For example, if users want to test "intrinsic.linear_optimisation" with VCS emulator,
and compare the result with verilator-emulator,
they will have to write "nix build
.#t1.blastoise.ip.vcs-emu.cases.intrinsic.linear_optimisation",
then ".#t1.blastoise.ip.verilator-emu.cases.intrinsic.linear_optimisation"

With the new script, the test flow is separate into different phrases:

* Firstly, get into the dev-mode shell: `nix develop .#dev-mode`
* Then, set the config: `set_config blastoise`
* Users can inspect RTL with simple command too: `build vcs-emu-rtl`
* To switch between verilator and VCS, they can use: `set_emulator
  vcs-emu` or `set_emulator verilator-emu`
* Finally, run the case: `test intrinsic.linear_optimisation`

Signed-off-by: Avimitin <[email protected]>

nix/pkgs/dev-mode/dev-mode.sh

@@ -1,3 +1,5 @@
+export TMPDIR=/tmp
+
 # prefer terminal safe colored and bold text when tput is supported
 if tput setaf 0 &>/dev/null; then
   ALL_OFF="$(tput sgr0)"
@@ -210,8 +212,14 @@ test() {
     return 1
   fi
 
+  DEBUG=${DEBUG:-0}
+  caseAttr=".#t1.$_CFG.ip.$_EMU.cases.$case.emu-result"
+  if (( DEBUG )); then
+    caseAttr="$caseAttr.debug"
+  fi
+
   info "Running test case $case with emulator $_EMU, output result to ./result-$case"
-  nix build --no-warn-dirty --out-link ./result-$case ".#t1.$_CFG.ip.$_EMU.cases.$case.emu-result"
+  nix build --no-warn-dirty --out-link ./result-$case "$caseAttr" $@
   ls -l ./result-$case/
 }