shipwright: fix dev builds

Fallback to empty string for GIT_COMMIT_TAG (this is the behavior of the
CMake as well).
https://github.com/HarbourMasters/Shipwright/blob/1b6dc13491460462f3a04e56b8fe1a28ada5d2a3/CMakeLists.txt#L68-L70

Grab --port-ver from the CMake cache instead of passing
finalAttrs.version. For tagged releases that works fine but the game
expects the --port-ver to match the CMake project version even for dev
builds so failing to do this will result in the game failing to boot
since it thinks there's a version mismatch between the executable and
the OTR in the derivation.

Author: Sirius902

pkgs/by-name/sh/shipwright/package.nix

@@ -124,7 +124,7 @@ stdenv.mkDerivation (finalAttrs: {
       cd $out
       git branch --show-current > GIT_BRANCH
       git rev-parse --short=7 HEAD > GIT_COMMIT_HASH
-      git describe --tags --abbrev=0 --exact-match HEAD > GIT_COMMIT_TAG
+      (git describe --tags --abbrev=0 --exact-match HEAD 2>/dev/null || echo "") > GIT_COMMIT_TAG
       rm -rf .git
     '';
   };
@@ -213,10 +213,11 @@ stdenv.mkDerivation (finalAttrs: {
   '';
 
   postBuild = ''
+    port_ver=$(grep CMAKE_PROJECT_VERSION: "$PWD/CMakeCache.txt" | cut -d= -f2)
     cp ${gamecontrollerdb}/gamecontrollerdb.txt gamecontrollerdb.txt
     mv ../libultraship/src/graphic/Fast3D/shaders ../soh/assets/custom
     pushd ../OTRExporter
-    python3 ./extract_assets.py -z ../build/ZAPD/ZAPD.out --norom --xml-root ../soh/assets/xml --custom-assets-path ../soh/assets/custom --custom-otr-file soh.otr --port-ver ${finalAttrs.version}
+    python3 ./extract_assets.py -z ../build/ZAPD/ZAPD.out --norom --xml-root ../soh/assets/xml --custom-assets-path ../soh/assets/custom --custom-otr-file soh.otr --port-ver $port_ver
     popd
   '';