build(docker): work around Windows Git Bash build image issues

Permission denied errors. Still there, but the build completes.

Author: thewtex

src/docker/itk-wasm/Dockerfile

@@ -40,8 +40,7 @@ COPY web-build /usr/local/bin/
 
 # Trigger Emscripten to cache builds of required system libraries
 ADD median-filter-pipelineCopy /median-filter-pipelineCopy
-ADD populate-cache.sh /usr/local/bin/populate-cache.sh
-RUN /usr/local/bin/populate-cache.sh && rm /usr/local/bin/populate-cache.sh
+RUN if [ $BASE_IMAGE = "itkwasm/emscripten-base" ]; then cd /median-filter-pipelineCopy; /usr/local/bin/web-build emscripten-build -DCMAKE_EXE_LINKER_FLAGS='-flto=thin -s DISABLE_EXCEPTION_CATCHING=0'; rm -rf ./web-build; /usr/local/bin/web-build emscripten-build -DCMAKE_EXE_LINKER_FLAGS='-flto -s DISABLE_EXCEPTION_CATCHING=0'; rm -rf ./web-build; /usr/local/bin/web-build emscripten-build -DCMAKE_EXE_LINKER_FLAGS='-fno-lto -s DISABLE_EXCEPTION_CATCHING=1'; rm -rf /median-filter-pipelineCopy; chmod -R 777 /emsdk/upstream/emscripten/cache; fi
 
 # Build-time metadata as defined at http://label-schema.org
 ARG BUILD_DATE