fix(nix): fix nix build with waveform support

.github/workflows/ci.yml

@@ -111,3 +111,15 @@ jobs:
         run: |
           sed -i -e "s/--threads [^ ]*/--threads `nproc`/" Makefile
           make -j `nproc` bolt dutName=ysyx3
+
+  nix:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+      - uses: cachix/install-nix-action@v31
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+      - name: Check if nix builds
+        run: |
+          nix build .#gsim
+          nix build .#gsim-static

Makefile

@@ -157,8 +157,9 @@ CXXFLAGS += -ggdb -O3 -MMD $(addprefix -I,$(GSIM_INC_DIR)) -Wall -Werror --std=c
 GSIM_VERSION ?= $(shell git describe --tags --always --dirty 2>/dev/null || echo UNKNOWN)
 GSIM_BUILD_DATE ?= $(shell date -u +%Y-%m-%dT%H:%M:%SZ 2>/dev/null || echo UNKNOWN)
 GSIM_CXX_VERSION ?= $(shell $(CXX) --version 2>/dev/null | head -n 1 || echo UNKNOWN)
+GSIM_INCLUDE_DIR ?= $(abspath include)
 CXXFLAGS += '-DGSIM_VERSION="$(GSIM_VERSION)"' '-DGSIM_BUILD_DATE="$(GSIM_BUILD_DATE)"' '-DGSIM_CXX_VERSION="$(GSIM_CXX_VERSION)"'
-CXXFLAGS += '-DGSIM_INCLUDE_DIR="$(abspath include)"'
+CXXFLAGS += '-DGSIM_INCLUDE_DIR="$(GSIM_INCLUDE_DIR)"'
 
 ifeq ($(DWARF4),1)
 	CXXFLAGS += -gdwarf-4

flake.nix

@@ -30,20 +30,24 @@
               pkgs.flex
               pkgs.gmp
               pkgs.jemalloc
+              pkgs.zlib
             ];
 
             makeFlags = [
               # gsim defaults to /bin/bash, which is not guaranteed in NixOS
               "SHELL=${llvm.stdenv.shell}"
               # nix builder does not have access to .git, so 'git describe' will fail, we need pass this explicitly
               "GSIM_VERSION=${version}"
+              # override GSIM_INCLUDE_DIR to real output path
+              "GSIM_INCLUDE_DIR=${builtins.placeholder "out"}/include"
               # override default build target to avoid running tests
               "build-gsim"
             ];
 
             installPhase = ''
               runHook preInstall
               install -Dm755 build/gsim/gsim $out/bin/gsim
+              install -Dm644 include/gsimFst.h $out/include/gsimFst.h
               runHook postInstall
             '';