add ci build for all at32, use linker and startup from mcu cmsis instead of local files

examples/build_system/cmake/cpu/cortex-m4-nofpu.cmake

@@ -0,0 +1,30 @@
+if (TOOLCHAIN STREQUAL "gcc")
+  set(TOOLCHAIN_COMMON_FLAGS
+    -mthumb
+    -mcpu=cortex-m4
+    -mfloat-abi=soft
+    )
+  if (NOT DEFINED FREERTOS_PORT)
+    set(FREERTOS_PORT GCC_ARM_CM3 CACHE INTERNAL "")
+  endif ()
+
+elseif (TOOLCHAIN STREQUAL "clang")
+  set(TOOLCHAIN_COMMON_FLAGS
+    --target=arm-none-eabi
+    -mcpu=cortex-m4
+    )
+  if (NOT DEFINED FREERTOS_PORT)
+    set(FREERTOS_PORT GCC_ARM_CM3 CACHE INTERNAL "")
+  endif ()
+
+elseif (TOOLCHAIN STREQUAL "iar")
+  set(TOOLCHAIN_COMMON_FLAGS
+    --cpu cortex-m4
+    --fpu none
+    )
+
+  if (NOT DEFINED FREERTOS_PORT)
+    set(FREERTOS_PORT IAR_ARM_CM3 CACHE INTERNAL "")
+  endif ()
+
+endif ()

examples/build_system/make/cpu/cortex-m4-nofpu.mk

@@ -0,0 +1,20 @@
+ifeq ($(TOOLCHAIN),gcc)
+  CFLAGS += \
+    -mthumb \
+    -mcpu=cortex-m4 \
+    -mfloat-abi=soft
+
+else ifeq ($(TOOLCHAIN),clang)
+  CFLAGS += \
+	  --target=arm-none-eabi \
+	  -mcpu=cortex-m4
+
+else ifeq ($(TOOLCHAIN),iar)
+  CFLAGS += --cpu cortex-m4 --fpu none
+  ASFLAGS += --cpu cortex-m4 --fpu none
+
+else
+  $(error "TOOLCHAIN is not supported")
+endif
+
+FREERTOS_PORTABLE_SRC ?= $(FREERTOS_PORTABLE_PATH)/ARM_CM3

examples/device/net_lwip_webserver/skip.txt

@@ -15,6 +15,7 @@ mcu:STM32N6
 family:broadcom_64bit
 family:broadcom_32bit
 family:espressif
+board:AT_START_F425
 board:curiosity_nano
 board:frdm_kl25z
 # lpc55 has weird error 'ncm_interface' causes a section type conflict with 'ntb_parameters'