remove git submodule for QP/C repo. Use FetchContent instead.

 But only if CMS_QPC_TOP_DIR is not defined.
 This allows a higher level project to avoid having duplicate QP/C code in a project's source code tree.

Author: mattheweshleman

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "externals/qpc"]
-	path = externals/qpc
-	url = git@github.com:QuantumLeaps/qpc.git

CMakeLists.txt

@@ -1,5 +1,6 @@
 cmake_minimum_required(VERSION 3.16)
 project(cpputest-for-qpc-lib)
+include(FetchContent)
 
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_C_STANDARD 11)
@@ -8,11 +9,17 @@ add_compile_options(-Wall -Wextra -Werror)
 
 set(CMS_EXTERNALS_TOP_DIR ${CMAKE_CURRENT_SOURCE_DIR}/externals)
 set(CMS_CMAKE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/cpputest-for-qpc-lib/cmake)
-set(CMS_QPC_TOP_DIR ${CMS_EXTERNALS_TOP_DIR}/qpc)
 
-include(${CMS_CMAKE_DIR}/qpcCMakeSupport.cmake)
-
-# todo: if not set then use externals
-set(CMS_QPC_TOP_DIR ${EXTERNALS_TOP_DIR}/qpc)
+if(NOT DEFINED CMS_QPC_TOP_DIR)
+    set(CMS_QPC_TOP_DIR ${CMS_EXTERNALS_TOP_DIR}/qpc)
+    FetchContent_Declare(qpc
+            GIT_REPOSITORY https://github.com/QuantumLeaps/qpc.git
+            GIT_TAG        fcea9943bbeeca49c66ce124d4d71467f6e2661e #7.3.3
+            SOURCE_DIR     ${CMS_QPC_TOP_DIR}
+    )
+    message("Fetching QP/C git repository")
+    FetchContent_MakeAvailable(qpc)
+endif(NOT DEFINED CMS_QPC_TOP_DIR)
 
+include(${CMS_CMAKE_DIR}/qpcCMakeSupport.cmake)
 add_subdirectory(cpputest-for-qpc-lib)

externals/.gitignore

@@ -0,0 +1 @@
+qpc/