feat(ulp): build legacy ULP APIs through CMake v2 shim

components/esp_hal_dma/CMakeLists.txt

@@ -10,6 +10,15 @@ if(EXISTS "${CMAKE_CURRENT_LIST_DIR}/${target}/include")
     list(APPEND public_include "${target}/include")
 endif()
 
+# TODO(IDF-15991): potentially remove __ULP_BUILD handling from esp_hal_dma
+if(__ULP_BUILD)
+    # LP-core SPI uses components/esp_hal_gpspi/include/hal/spi_slave_hd_hal.h,
+    # whose public headers include DMA HAL descriptor types.
+    idf_component_register(INCLUDE_DIRS ${public_include}
+                           REQUIRES soc hal)
+    return()
+endif()
+
 if(CONFIG_SOC_GDMA_SUPPORTED)
     list(APPEND srcs "gdma_hal_top.c" "${target}/gdma_periph.c")