remove build_env.sh from Dockerfile

Dockerfile

@@ -18,13 +18,9 @@ ARG BUILDPLATFORM
 # build_env.sh is used to capture the environmental changes required by the build step since RUN
 # environment state is not otherwise persistent.
 RUN if [ "$TARGETPLATFORM" = "linux/arm64" ] && [ "$BUILDPLATFORM" != "linux/arm64" ]; then \
-  apt-get update && apt-get install -y gcc-aarch64-linux-gnu && \
-  echo "export CC=aarch64-linux-gnu-gcc" > ./build_env.sh \
+  apt-get update && apt-get install -y gcc-aarch64-linux-gnu \
   ; elif [ "$TARGETPLATFORM" = "linux/amd64" ] && [ "$BUILDPLATFORM" != "linux/amd64" ]; then \
-  apt-get update && apt-get install -y gcc-x86-64-linux-gnu && \
-  echo "export CC=x86_64-linux-gnu-gcc" > ./build_env.sh \
-  ; else \
-  echo "export CC=gcc" > ./build_env.sh \
+  apt-get update && apt-get install -y gcc-x86-64-linux-gnu \
   ; fi
 
 # Copy avalanche dependencies first (intermediate docker image caching)
@@ -44,10 +40,7 @@ RUN [ -d ./build ] && rm -rf ./build/* || true
 ARG SUBNET_EVM_COMMIT
 ARG CURRENT_BRANCH
 
-RUN . ./build_env.sh && \
-  echo "{CC=$CC, TARGETPLATFORM=$TARGETPLATFORM, BUILDPLATFORM=$BUILDPLATFORM}" && \
-  export GOARCH=$(echo ${TARGETPLATFORM} | cut -d / -f2) && \
-  export SUBNET_EVM_COMMIT=$SUBNET_EVM_COMMIT && export CURRENT_BRANCH=$CURRENT_BRANCH && ./scripts/build.sh build/subnet-evm
+RUN export SUBNET_EVM_COMMIT=$SUBNET_EVM_COMMIT && export CURRENT_BRANCH=$CURRENT_BRANCH && ./scripts/build.sh build/subnet-evm
 
 # ============= Cleanup Stage ================
 FROM $AVALANCHEGO_NODE_IMAGE AS builtImage