build: Split core into spearate library (#15)

Separate core into separate library for better build performance and dependencies management.

CMakeLists.txt

@@ -9,6 +9,9 @@ project(
     VERSION 0.1.0
 )
 
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
 # Enable exporting compile commands
 set(CMAKE_EXPORT_COMPILE_COMMANDS
     ON

src/spider/CMakeLists.txt

@@ -11,19 +11,18 @@ set(SPIDER_CORE_SOURCES
     CACHE INTERNAL
     "spider core source files"
 )
+
+if(SPIDER_USE_STATIC_LIBS)
+    add_library(spider_core STATIC)
+else()
+    add_library(spider_core SHARED)
+endif()
+target_sources(spider_core PRIVATE ${SPIDER_CORE_SOURCES})
+target_link_libraries(spider_core PUBLIC Boost::boost PRIVATE absl::flat_hash_map)
+
 set(SPIDER_WORKER_SOURCES worker/worker.cpp CACHE INTERNAL "spider worker source files")
 
 add_executable(spider_worker)
-target_compile_features(spider_worker PRIVATE cxx_std_20)
-target_sources(
-    spider_worker
-    PRIVATE
-        ${SPIDER_CORE_SOURCES}
-        ${SPIDER_WORKER_SOURCES}
-)
-target_link_libraries(
-    spider_worker
-    Boost::boost
-    absl::flat_hash_map
-)
+target_sources(spider_worker PRIVATE ${SPIDER_WORKER_SOURCES})
+target_link_libraries(spider_worker PRIVATE spider_core)
 add_executable(spider::worker ALIAS spider_worker)