Merge remote-tracking branch 'origin/master' into origin/release/1.8.x

Create a merge commit so that the RC1 tag appears correctly in release/1.8.x

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: I1a7d6cd9adbc010a866812e0e3871a7032cdc4f5
diff --git a/cmake/install.cmake b/cmake/install.cmake
index 3cba192..69db5a3 100644
--- a/cmake/install.cmake
+++ b/cmake/install.cmake
@@ -203,7 +203,4 @@
 include(${CMAKE_SOURCE_DIR}/lib/ext/tf-m-tests/install.cmake)
 
 ##################### Platform-specific installation ###########################
-
-if (EXISTS ${TARGET_PLATFORM_PATH}/install.cmake)
-    include(${TARGET_PLATFORM_PATH}/install.cmake)
-endif()
+include(${TARGET_PLATFORM_PATH}/install.cmake OPTIONAL)
diff --git a/config/check_config.cmake b/config/check_config.cmake
index 482236f..025dbad 100644
--- a/config/check_config.cmake
+++ b/config/check_config.cmake
@@ -120,6 +120,4 @@
 
 ###################### Platform-specific checks ################################
 
-if (EXISTS ${TARGET_PLATFORM_PATH}/check_config.cmake)
-    include(${TARGET_PLATFORM_PATH}/check_config.cmake)
-endif()
+include(${TARGET_PLATFORM_PATH}/check_config.cmake OPTIONAL)
diff --git a/config/post_config.cmake b/config/post_config.cmake
index 6872820..f4fdece 100644
--- a/config/post_config.cmake
+++ b/config/post_config.cmake
@@ -9,9 +9,7 @@
 include(config/config_base.cmake)
 
 # Load regression configs overrided by platform
-if(EXISTS ${TARGET_PLATFORM_PATH}/reg_config_override.cmake)
-    include(${TARGET_PLATFORM_PATH}/reg_config_override.cmake)
-endif()
+include(${TARGET_PLATFORM_PATH}/reg_config_override.cmake OPTIONAL)
 
 # Fetch tf-m-tests repo during config, if NS or regression test is required.
 # Therefore tf-m-tests configs can be set with TF-M configs since their configs
diff --git a/config/set_config.cmake b/config/set_config.cmake
index 3966eb4..a87ebeb 100644
--- a/config/set_config.cmake
+++ b/config/set_config.cmake
@@ -21,14 +21,10 @@
 
 # Load build type config, setting options not already set
 string(TOLOWER "${CMAKE_BUILD_TYPE}" CMAKE_BUILD_TYPE_LOWERCASE)
-if(EXISTS ${CMAKE_SOURCE_DIR}/config/build_type/${CMAKE_BUILD_TYPE_LOWERCASE}.cmake)
-    include(${CMAKE_SOURCE_DIR}/config/build_type/${CMAKE_BUILD_TYPE_LOWERCASE}.cmake)
-endif()
+include(${CMAKE_SOURCE_DIR}/config/build_type/${CMAKE_BUILD_TYPE_LOWERCASE}.cmake OPTIONAL)
 
 # Load platform config, setting options not already set
-if(EXISTS ${TARGET_PLATFORM_PATH}/config.cmake)
-    include(${TARGET_PLATFORM_PATH}/config.cmake)
-endif()
+include(${TARGET_PLATFORM_PATH}/config.cmake OPTIONAL)
 
 # Parse tf-m-tests config prior to platform specific config.cmake
 # Some platforms select different configuration according when regression tests