CMake: Add support for SiLabs EFR32MG12 targets

Author: hugueskamba

targets/TARGET_Silicon_Labs/TARGET_EFM32/TARGET_EFR32MG12/CMakeLists.txt

@@ -0,0 +1,32 @@
+# Copyright (c) 2020 ARM Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+if("TB_SENSE_12" IN_LIST MBED_TARGET_LABELS)
+    target_include_directories(mbed-core
+        INTERFACE
+            TARGET_TB_SENSE_12
+    )
+endif()
+
+if(${MBED_TOOLCHAIN} STREQUAL "ARM")
+    set(LINKER_FILE device/TOOLCHAIN_ARM_STD/efr32mg12p.sct)
+    set(STARTUP_FILE device/TOOLCHAIN_ARM_STD/startup_efr32mg12p.S)
+elseif(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
+    set(LINKER_FILE device/TOOLCHAIN_GCC_ARM/efr32mg12p.ld)
+    set(STARTUP_FILE device/TOOLCHAIN_GCC_ARM/startup_efr32mg12p.S)
+endif()
+
+set_property(GLOBAL PROPERTY MBED_TARGET_LINKER_FILE ${CMAKE_CURRENT_SOURCE_DIR}/${LINKER_FILE})
+
+target_include_directories(mbed-core
+    INTERFACE
+        device
+)
+
+target_sources(mbed-core
+    INTERFACE
+        PeripheralPins.c
+
+        device/system_efr32mg12p.c
+        ${STARTUP_FILE}
+)

targets/TARGET_Silicon_Labs/TARGET_EFM32/TARGET_EFR32MG12/device/TOOLCHAIN_ARM_STD/efr32mg12p.sct

@@ -1,4 +1,4 @@
-#! armcc -E
+#! armclang -E --target=arm-arm-none-eabi -x c -mcpu=cortex-m4
 ; *************************************************************
 ; *** Scatter-Loading Description File generated by uVision ***
 ; *************************************************************