Add libenvpp as submodule. Include it in cmake.

Test config properly parses correct env vars or reports when they can not be parsed.
Add test for deprecated env vars.
libenvpp checked out at v1.1 tag.

.gitmodules

@@ -10,3 +10,6 @@
 [submodule "vendor/Catch2"]
 	path = vendor/Catch2
 	url = https://github.com/catchorg/Catch2.git
+[submodule "vendor/libenvpp"]
+	path = vendor/libenvpp
+	url = https://github.com/ph3at/libenvpp.git

CMakeLists.txt

@@ -64,7 +64,7 @@ else()
     set(CELERITY_SYCL_IMPL "${AVAILABLE_SYCL_IMPLS}")
     message(STATUS "Automatically chooosing ${CELERITY_SYCL_IMPL} because it is the only SYCL implementation available")
   endif()
-endif ()
+endif()
 
 set(CELERITY_DPCPP_TARGETS "spir64" CACHE STRING "Intel DPC++ targets")
 if(CELERITY_SYCL_IMPL STREQUAL "DPC++")
@@ -179,6 +179,9 @@ endif()
 fetch_content_from_submodule(Catch2 vendor/Catch2)
 list(APPEND CMAKE_MODULE_PATH ${catch2_SOURCE_DIR}/extras)
 
+set(LIBENVPP_INSTALL ON CACHE BOOL "" FORCE)
+fetch_content_from_submodule(libenvpp vendor/libenvpp)
+
 configure_file(include/version.h.in include/version.h @ONLY)
 
 # Add includes to library so they show up in IDEs
@@ -259,6 +262,7 @@ target_link_libraries(celerity_runtime PUBLIC
   fmt::fmt
   spdlog::spdlog
   gch::small_vector
+  libenvpp::libenvpp
   ${SYCL_LIB}
 )
 

cmake/celerity-config.cmake.in

@@ -22,6 +22,7 @@ find_dependency(Threads REQUIRED)
 find_dependency(fmt REQUIRED)
 find_dependency(spdlog REQUIRED)
 find_dependency(small_vector REQUIRED)
+find_dependency(libenvpp REQUIRED)
 
 if(CELERITY_SYCL_IMPL STREQUAL "hipSYCL")
   if(NOT DEFINED HIPSYCL_TARGETS AND NOT "@HIPSYCL_TARGETS@" STREQUAL "")

include/config.h

@@ -2,6 +2,8 @@
 
 #include <cstddef>
 #include <optional>
+#include <string_view>
+#include <vector>
 
 namespace celerity {
 namespace detail {
@@ -47,7 +49,7 @@ namespace detail {
 		std::optional<device_config> m_device_cfg;
 		std::optional<bool> m_enable_device_profiling;
 		size_t m_graph_print_max_verts = 200;
-		int m_dry_run_nodes = 0;
+		size_t m_dry_run_nodes = 0;
 	};
 
 } // namespace detail