Allow building without CDL++ installed

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "lib/cdlpp-db"]
 	path = lib/cdlpp-db
 	url = https://gitlab.com/niansa/cdlpp-db.git
+[submodule "lib/cdlpp"]
+	path = lib/cdlpp
+	url = https://gitlab.com/niansa/cdlpp.git

CMakeLists.txt

@@ -3,8 +3,10 @@ cmake_minimum_required(VERSION 3.5)
 project(tuxiflux LANGUAGES CXX)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(BUILD_SHARED_LIBS No)
 
 include(embed.cmake)
+include(cdlpp.cmake)
 
 add_compile_definitions(COMPILER_ID="${CMAKE_CXX_COMPILER_ID}")
 add_compile_definitions(COMPILER_VERSION="${CMAKE_CXX_COMPILER_VERSION}")
@@ -37,17 +39,18 @@ if (cpuid_FOUND)
 endif()
 
 find_package(PkgConfig REQUIRED)
-pkg_check_modules(cdlpp REQUIRED IMPORTED_TARGET cdlpp)
 pkg_check_modules(fmt REQUIRED IMPORTED_TARGET fmt)
 
 target_link_libraries(${PROJECT_NAME} PUBLIC
-        PkgConfig::cdlpp PkgConfig::fmt cdlpp-db)
+        PkgConfig::fmt cdlpp-db)
+
+use_cdlpp(${PROJECT_NAME} lib/cdlpp)
 
 if (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
     option(ENABLE_EVAL "ENABLE_EVAL" ON)
     if (${ENABLE_EVAL})
         target_link_libraries(${PROJECT_NAME} PUBLIC
-                -ldl)
+                dl)
         add_compile_definitions(ENABLE_EVAL)
     endif()
 endif()

cdlpp.cmake

@@ -0,0 +1,19 @@
+function(use_cdlpp target cdlpp_src_dir)
+    find_package(PkgConfig REQUIRED)
+    pkg_check_modules(cdlpp IMPORTED_TARGET cdlpp)
+
+    option(FORCE_SUBMODULE_CDLPP "Use CDLPP from submodule even if installed in system" No)
+    if(cdlpp_FOUND OR FORCE_SUBMODULE_CDLPP)
+        set(CDLPP_LIB PkgConfig::cdlpp)
+    else()
+        execute_process(
+            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+            COMMAND git submodule update --init --recursive --depth 1
+        )
+        add_subdirectory(${cdlpp_src_dir})
+        set(CDLPP_LIB "cdlpp")
+    endif()
+
+    target_link_libraries(${PROJECT_NAME} PUBLIC
+            ${CDLPP_LIB})
+endfunction()

lib/cdlpp

@@ -0,0 +1 @@
+Subproject commit 50fb353a5ffe4c732810ab9bd1628be12b25eb54