raft: move algorithm code to src/lib/raft

Raft algorithm code does not depend on box anymore, and is moved
to src/lib/raft.

This is done to be able to unit test raft similarly to swim - with
virtual event loop, network, time, and disk. Using any number of
instances. That will allow to cover all crazy and rare cases
possible in raft, but without problems of functional tests
stability and clumsiness.

Part of #5303

src/box/CMakeLists.txt

@@ -169,7 +169,6 @@ add_library(box STATIC
     port.c
     txn.c
     txn_limbo.c
-    raftlib.c
     raft.c
     box.cc
     gc.c
@@ -263,6 +262,6 @@ add_custom_command(OUTPUT ${SQL_BIN_DIR}/opcodes.c
         ${SQL_BIN_DIR}/opcodes.h)
 
 target_link_libraries(box box_error tuple stat xrow xlog vclock crc32 scramble
-                      ${common_libraries})
+                      raft ${common_libraries})
 
 add_dependencies(box build_bundled_libs generate_sql_files)

src/box/raft.h

@@ -29,7 +29,7 @@
  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
-#include "raftlib.h"
+#include "raft/raft.h"
 
 #if defined(__cplusplus)
 extern "C" {

src/lib/CMakeLists.txt

@@ -14,6 +14,7 @@ add_subdirectory(crypto)
 add_subdirectory(swim)
 add_subdirectory(mpstream)
 add_subdirectory(vclock)
+add_subdirectory(raft)
 if(ENABLE_BUNDLED_MSGPUCK)
     add_subdirectory(msgpuck EXCLUDE_FROM_ALL)
 endif()

src/lib/raft/CMakeLists.txt

+set(lib_sources
+    raft.c
+)
+
+set_source_files_compile_flags(${lib_sources})
+add_library(raft STATIC ${lib_sources})
+target_link_libraries(raft core vclock)