Add linkermap for size analysis (#1136)

* add NO_LTO option to make
* add linkermap submodule and linkermap target
* add linkermap to ci build
* linkermap doesn't work with esp32sx map file yet
* add note for linkermap target

.github/workflows/build.yml

@@ -66,6 +66,12 @@ jobs:
     - name: Checkout common submodules in lib
       run: git submodule update --init lib/FreeRTOS-Kernel lib/lwip lib/sct_neopixel
 
+    - name: Checkout hathach/linkermap
+      uses: actions/checkout@v2
+      with:
+         repository: hathach/linkermap
+         path: linkermap
+
     - name: Checkout pico-sdk
       if: matrix.family == 'rp2040'
       run: |
@@ -95,6 +101,14 @@ jobs:
     - name: Build
       run: python3 tools/build_family.py ${{ matrix.family }}
 
+    - name: Linker Map
+      run: |
+        pip install linkermap/
+        for ex in `ls -d examples/device/*/`; do \
+          find ${ex} -name *.map -print -quit | \
+          xargs -I % sh -c 'echo "::group::%"; linkermap -v %; echo "::endgroup::"'; \
+        done
+
   # ---------------------------------------
   # Build all no-family (opharned) boards
   # ---------------------------------------