CMake: Add test for multiple-executable support

Add a test to build two executables in two directories under a single
project.

Author: LDong-Arm

.github/workflows/test_building_multiple_executables.yml

@@ -0,0 +1,28 @@
+name: test building multiple executables with CMake
+
+on: [pull_request]
+
+jobs:
+  multiple-executables-example:
+    runs-on: ubuntu-latest
+    container: mbedos/mbed-os-env:latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Build the multiple_executables example
+        run: |
+            mbedtools compile \
+              -t GCC_ARM \
+              -m ARM_MUSCA_S1 \
+              --program-path tools/cmake/tests/multiple_executables/ \
+              --mbed-os-path .
+
+      - name: Verify the post-build command has run successfully on each image
+        run: |
+            APP1=tools/cmake/tests/multiple_executables/cmake_build/ARM_MUSCA_S1/develop/GCC_ARM/app1/app1.bin
+            APP2=tools/cmake/tests/multiple_executables/cmake_build/ARM_MUSCA_S1/develop/GCC_ARM/app2/app2.bin
+            BOOTLOADER=targets/TARGET_ARM_SSG/TARGET_MUSCA_S1/bl2.bin
+            BOOTLOADER_SIZE=`du -b targets/TARGET_ARM_SSG/TARGET_MUSCA_S1/bl2.bin | cut -f1`
+            cmp -n $BOOTLOADER_SIZE $APP1 $BOOTLOADER
+            cmp -n $BOOTLOADER_SIZE $APP2 $BOOTLOADER

tools/cmake/tests/multiple_executables/CMakeLists.txt

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+# Copyright (c) 2021 Arm Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.19.0)
+
+set(MBED_PATH "${CMAKE_CURRENT_SOURCE_DIR}/../../../..")
+set(MBED_CONFIG_PATH "${CMAKE_CURRENT_BINARY_DIR}")
+
+include("${MBED_PATH}/tools/cmake/app.cmake")
+
+project(multiple_executables)
+
+add_subdirectory("${MBED_PATH}" "mbed-os-build")
+
+add_subdirectory(app1)
+add_subdirectory(app2)

tools/cmake/tests/multiple_executables/app1/CMakeLists.txt

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+# Copyright (c) 2021 Arm Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+add_executable(app1 main.cpp)
+
+target_link_libraries(app1 mbed-os)
+
+mbed_set_post_build(app1)

tools/cmake/tests/multiple_executables/app1/main.cpp

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2021 Arm Limited
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "mbed.h"
+
+int main()
+{
+    printf("Application 1\n");
+    return 0;
+}

tools/cmake/tests/multiple_executables/app2/CMakeLists.txt

@@ -0,0 +1,8 @@
+# Copyright (c) 2021 Arm Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+add_executable(app2 main.cpp)
+
+target_link_libraries(app2 mbed-os)
+
+mbed_set_post_build(app2)

tools/cmake/tests/multiple_executables/app2/main.cpp

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2021 Arm Limited
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "mbed.h"
+
+int main()
+{
+    printf("Application 2\n");
+    return 0;
+}