export sdkroot instead of repeating its addition per command

Author: alonme

.github/workflows/jit.yml

@@ -131,9 +131,9 @@ jobs:
           brew update
           find /usr/local/bin -lname '*/Library/Frameworks/Python.framework/*' -delete
           brew install llvm@${{ matrix.llvm }}
-          SDKROOT="$(xcrun --show-sdk-path)" \
-            ./configure --enable-experimental-jit ${{ matrix.debug && '--with-pydebug' || '--enable-optimizations --with-lto' }}
-          SDKROOT="$(xcrun --show-sdk-path)" make all --jobs 4
+          export SDKROOT="$(xcrun --show-sdk-path)"
+          ./configure --enable-experimental-jit ${{ matrix.debug && '--with-pydebug' || '--enable-optimizations --with-lto' }}
+          make all --jobs 4
           ./python.exe -m test --multiprocess 0 --timeout 4500 --verbose2 --verbose3
 
       - name: Native Linux