Set binary folder for external components correctly

cmake/opentelemetry-build-external-component.cmake

@@ -1,6 +1,16 @@
 # Copyright The OpenTelemetry Authors
 # SPDX-License-Identifier: Apache-2.0
 
+function(get_directory_name_in_path PATH_VAR RESULT_VAR)
+  # get_filename_component does not work with paths ending in / or \, so remove it.
+  string(REGEX REPLACE "/$" "" PATH_TRIMMED "${PATH_VAR}")
+  string(REGEX REPLACE "\\$" "" PATH_TRIMMED "${PATH_VAR}")
+
+  get_filename_component(DIR_NAME ${PATH_TRIMMED} NAME)
+
+  set(${RESULT_VAR} "${DIR_NAME}" PARENT_SCOPE)
+endfunction()
+
 # Enable building external components through otel-cpp build
 # The config options are
 #  - OPENTELEMETRY_EXTERNAL_COMPONENT_PATH - Setting local paths of the external
@@ -14,14 +24,16 @@ if(OPENTELEMETRY_EXTERNAL_COMPONENT_PATH)
   # Add custom component path to build tree and consolidate binary artifacts in
   # current project binary output directory.
   foreach(DIR IN LISTS OPENTELEMETRY_EXTERNAL_COMPONENT_PATH)
-    add_subdirectory(${DIR} ${PROJECT_BINARY_DIR}/external)
+    get_directory_name_in_path(${DIR} EXTERNAL_EXPORTER_DIR_NAME)
+    add_subdirectory(${DIR} ${PROJECT_BINARY_DIR}/external/${EXTERNAL_EXPORTER_DIR_NAME})
   endforeach()
 elseif(DEFINED ENV{OPENTELEMETRY_EXTERNAL_COMPONENT_PATH})
   # Add custom component path to build tree and consolidate binary artifacts in
   # current project binary output directory.
   set(OPENTELEMETRY_EXTERNAL_COMPONENT_PATH_VAR $ENV{OPENTELEMETRY_EXTERNAL_COMPONENT_PATH})
   foreach(DIR IN LISTS OPENTELEMETRY_EXTERNAL_COMPONENT_PATH_VAR)
-    add_subdirectory(${DIR} ${PROJECT_BINARY_DIR}/external)
+    get_directory_name_in_path(${DIR} EXTERNAL_EXPORTER_DIR_NAME)
+    add_subdirectory(${DIR} ${PROJECT_BINARY_DIR}/external/${EXTERNAL_EXPORTER_DIR_NAME})
   endforeach()
 elseif(DEFINED $ENV{OPENTELEMETRY_EXTERNAL_COMPONENT_URL})
   # This option requires CMake 3.11+: add standard remote repo to build tree.