tools/ci.sh: Build user C modules for esp32.

Builds the esp32 port against the example C and CXX modules.
Signed-off-by: Michael O'Cleirigh <michael.ocleirigh@rivulet.ca>

tools/ci.sh

@@ -100,6 +100,8 @@ function ci_esp32_build {
     make ${MAKEOPTS} -C mpy-cross
     make ${MAKEOPTS} -C ports/esp32 submodules
     make ${MAKEOPTS} -C ports/esp32
+    make ${MAKEOPTS} -C ports/esp32 clean
+    make ${MAKEOPTS} -C ports/esp32 USER_C_MODULES=../../../examples/usercmodule/micropython.cmake
 }
 
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