diff --git a/CMakeLists.txt b/CMakeLists.txt
index 18a14cb0..5a0cbb4e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -32,9 +32,9 @@ set(CMAKE_INCLUDE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake" ${CMAKE_INCLUDE_PATH}
 include(SetBuildParallelLevel)
 include(SetHardwareArch)
 
-if (ENABLE_LUAJIT_RANDOM_RA AND NOT USE_LUAJIT)
+if (ENABLE_LUAJIT_RANDOM_RA AND NOT IS_LUAJIT)
   message(FATAL_ERROR "Option ENABLE_LUAJIT_RANDOM_RA is LuaJIT-specific.")
-endif (ENABLE_LUAJIT_RANDOM_RA AND NOT USE_LUAJIT)
+endif()
 
 if (USE_LUA AND NOT LUA_VERSION)
   set(LUA_VERSION "master")
@@ -50,6 +50,20 @@ if (USE_LUA)
 elseif (USE_LUAJIT)
   include(BuildLuaJIT)
   build_luajit(${LUA_VERSION})
+  set(IS_LUAJIT TRUE)
+elseif (LUA_INCLUDE_DIR AND LUA_LIBRARIES AND LUA_EXECUTABLE)
+  message(STATUS "Lua library passed outside:")
+  message(STATUS "LUA_INCLUDE_DIR: ${LUA_INCLUDE_DIR}")
+  message(STATUS "LUA_LIBRARIES: ${LUA_LIBRARIES}")
+  message(STATUS "LUA_EXECUTABLE: ${LUA_EXECUTABLE}")
+
+  # When a path to a Lua library is passed outside, we should
+  # mimic a real CMake library to don't break code that depends on
+  # LUA_LIBRARIES.
+  add_library(bundled-liblua STATIC IMPORTED GLOBAL)
+  set_target_properties(bundled-liblua PROPERTIES
+    IMPORTED_LOCATION ${LUA_LIBRARIES})
+  set(LUA_LIBRARIES bundled-liblua)
 else ()
   message(FATAL_ERROR "No Lua is specified.")
 endif ()
@@ -70,7 +84,7 @@ endif()
 find_package(Protobuf)
 if (NOT Protobuf_FOUND)
     set(ENABLE_BUILD_PROTOBUF ON)
-endif (NOT Protobuf_FOUND)
+endif()
 
 SetBuildParallelLevel(CMAKE_BUILD_PARALLEL_LEVEL)
 
diff --git a/cmake/BuildLua.cmake b/cmake/BuildLua.cmake
index 40a15104..8d275f15 100644
--- a/cmake/BuildLua.cmake
+++ b/cmake/BuildLua.cmake
@@ -59,7 +59,7 @@ macro(build_lua LUA_VERSION)
 
     include(ExternalProject)
 
-    set(LUA_LIBRARIES ${PROJECT_BINARY_DIR}/lua-${LUA_VERSION}/source/liblua.a)
+    set(LUA_LIBRARY ${PROJECT_BINARY_DIR}/lua-${LUA_VERSION}/source/liblua.a)
     set(LUA_EXECUTABLE ${LUA_SOURCE_DIR}/lua)
 
     ExternalProject_Add(patched-lua-${LUA_VERSION}
@@ -82,12 +82,17 @@ macro(build_lua LUA_VERSION)
                                                  LDFLAGS=${LDFLAGS}
         INSTALL_COMMAND ""
 
-        BUILD_BYPRODUCTS ${LUA_LIBRARIES} ${LUA_EXECUTABLE}
+        BUILD_BYPRODUCTS ${LUA_LIBRARY} ${LUA_EXECUTABLE}
     )
 
+    add_library(bundled-liblua STATIC IMPORTED GLOBAL)
+    set_target_properties(bundled-liblua PROPERTIES
+      IMPORTED_LOCATION ${LUA_LIBRARY})
+    add_dependencies(bundled-liblua patched-lua-${LUA_VERSION})
+
+    set(LUA_LIBRARIES bundled-liblua)
     set(LUA_INCLUDE_DIR ${PROJECT_BINARY_DIR}/lua-${LUA_VERSION}/source/)
     set(LUA_VERSION_STRING "PUC Rio Lua ${LUA_VERSION}")
-    set(LUA_TARGET patched-lua-${LUA_VERSION})
 
     unset(LUA_BINARY_DIR)
     unset(LUA_PATCH_PATH)
diff --git a/cmake/BuildLuaJIT.cmake b/cmake/BuildLuaJIT.cmake
index 62d054e2..1e2419d1 100644
--- a/cmake/BuildLuaJIT.cmake
+++ b/cmake/BuildLuaJIT.cmake
@@ -83,7 +83,7 @@ macro(build_luajit LJ_VERSION)
 
     include(ExternalProject)
 
-    set(LUA_LIBRARIES ${LJ_SOURCE_DIR}/src/libluajit.a)
+    set(LUA_LIBRARY ${LJ_SOURCE_DIR}/src/libluajit.a)
     set(LUA_EXECUTABLE ${LJ_SOURCE_DIR}/src/luajit)
 
     ExternalProject_Add(patched-luajit-${LJ_VERSION}
@@ -110,13 +110,17 @@ macro(build_luajit LJ_VERSION)
                                                  -C src
         INSTALL_COMMAND ""
 
-        BUILD_BYPRODUCTS ${LUA_LIBRARIES} ${LUA_EXECUTABLE}
+        BUILD_BYPRODUCTS ${LUA_LIBRARY} ${LUA_EXECUTABLE}
     )
 
-    set(LUA_SOURCE_DIR ${LJ_SOURCE_DIR})
+    add_library(bundled-liblua STATIC IMPORTED GLOBAL)
+    set_target_properties(bundled-liblua PROPERTIES
+      IMPORTED_LOCATION ${LUA_LIBRARY})
+    add_dependencies(bundled-liblua patched-luajit-${LJ_VERSION})
+
+    set(LUA_LIBRARIES bundled-liblua)
     set(LUA_INCLUDE_DIR ${LJ_SOURCE_DIR}/src/)
     set(LUA_VERSION_STRING "LuaJIT ${LJ_VERSION}")
-    set(LUA_TARGET patched-luajit-${LJ_VERSION})
 
     unset(LJ_SOURCE_DIR)
     unset(LJ_BINARY_DIR)
diff --git a/cmake/CodeCoverage.cmake b/cmake/CodeCoverage.cmake
index d5fce4a4..0ec887f4 100644
--- a/cmake/CodeCoverage.cmake
+++ b/cmake/CodeCoverage.cmake
@@ -36,13 +36,13 @@ if(USE_LUA)
   set(GCOVR_OPTIONS ${GCOVR_OPTIONS} --object-directory ${LUA_SOURCE_DIR})
 endif ()
 
-if(USE_LUAJIT)
+if(IS_LUAJIT)
   # Exclude DynASM files, that contain a low-level VM code for CPUs.
   set(GCOVR_OPTIONS ${GCOVR_OPTIONS} --exclude ".*\.dasc")
   # Exclude buildvm source code, it's a project's build infrastructure.
   set(GCOVR_OPTIONS ${GCOVR_OPTIONS} --exclude ".*/host/")
   set(GCOVR_OPTIONS ${GCOVR_OPTIONS} --object-directory ${LUA_SOURCE_DIR}/src)
-endif (USE_LUAJIT)
+endif ()
 
 file(MAKE_DIRECTORY ${COVERAGE_DIR})
 add_custom_target(${target_name})
@@ -56,12 +56,12 @@ add_custom_command(TARGET ${target_name}
 # object files built with the GCC -fprofile-arcs option is executed.
 # https://gcc.gnu.org/onlinedocs/gcc/Gcov-Data-Files.html
 set(GCDA_FILES "${LUA_SOURCE_DIR}/*.gcda")
-if(USE_LUAJIT)
+if(IS_LUAJIT)
   # Files 'src/host/*.gcda' are not removed, because
   # CMake cannot remove recursively by globbing.
   # Files 'src/host/*.gcda' are not used for building coverage report.
   set(GCDA_FILES "${LUA_SOURCE_DIR}/src/*.gcda")
-endif(USE_LUAJIT)
+endif()
 add_custom_target(coverage-reset
   COMMENT "Reset code coverage counters"
   COMMAND ${CMAKE_COMMAND} -E rm -f ${GCDA_FILES}
diff --git a/cmake/utils.cmake b/cmake/utils.cmake
index 27669a82..fdf793bc 100644
--- a/cmake/utils.cmake
+++ b/cmake/utils.cmake
@@ -32,3 +32,13 @@ function(lua_source varname filename symbolname)
     set(var ${${varname}})
     set(${varname} ${var} ${dstfile} PARENT_SCOPE)
 endfunction()
+
+macro(AppendFlags flags)
+    foreach(flag ${ARGN})
+        if (${flags})
+            set(${flags} "${${flags}} ${flag}")
+        else()
+            set(${flags} "${flag}")
+        endif()
+    endforeach()
+endmacro()
diff --git a/libluamut/CMakeLists.txt b/libluamut/CMakeLists.txt
index 0b6888e7..2c57df6f 100644
--- a/libluamut/CMakeLists.txt
+++ b/libluamut/CMakeLists.txt
@@ -5,21 +5,21 @@ if (ENABLE_COV)
              -fcoverage-mapping -ftest-coverage)
   set(LDFLAGS ${LDFLAGS} -fprofile-instr-generate -fprofile-arcs
               -fcoverage-mapping -ftest-coverage)
-endif (ENABLE_COV)
+endif()
 
 set(LIB_LUA_MUTATE lua_mutate)
 add_library(${LIB_LUA_MUTATE} STATIC mutate.c)
 target_link_libraries(${LIB_LUA_MUTATE} PRIVATE ${LUA_LIBRARIES} ${LDFLAGS})
 target_include_directories(${LIB_LUA_MUTATE} PRIVATE ${LUA_INCLUDE_DIR})
 target_compile_options(${LIB_LUA_MUTATE} PRIVATE ${CFLAGS})
-add_dependencies(${LIB_LUA_MUTATE} ${LUA_TARGET})
+add_dependencies(${LIB_LUA_MUTATE} ${LUA_LIBRARIES})
 
 set(LIB_LUA_CROSSOVER lua_crossover)
 add_library(${LIB_LUA_CROSSOVER} STATIC crossover.c)
 target_link_libraries(${LIB_LUA_CROSSOVER} PRIVATE ${LUA_LIBRARIES} ${LDFLAGS})
 target_include_directories(${LIB_LUA_CROSSOVER} PRIVATE ${LUA_INCLUDE_DIR})
 target_compile_options(${LIB_LUA_CROSSOVER} PRIVATE ${CFLAGS})
-add_dependencies(${LIB_LUA_CROSSOVER} ${LUA_TARGET})
+add_dependencies(${LIB_LUA_CROSSOVER} ${LUA_LIBRARIES})
 
 if (ENABLE_INTERNAL_TESTS)
   add_subdirectory(tests)
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index ada0fcc3..9dd70ade 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -1,4 +1,4 @@
 add_subdirectory(capi)
 if (ENABLE_BONUS_TESTS)
   add_subdirectory(lapi)
-endif (ENABLE_BONUS_TESTS)
+endif()
diff --git a/tests/capi/CMakeLists.txt b/tests/capi/CMakeLists.txt
index cb24ef14..70b76dee 100644
--- a/tests/capi/CMakeLists.txt
+++ b/tests/capi/CMakeLists.txt
@@ -27,21 +27,30 @@ target_link_libraries(
         >
 )
 
+# The following condition looks unnecessary, it was added to fix
+# an issue for Sydr: in the Lua external project in the build
+# system the explicit build command is used:
+# BUILD_COMMAND cd <SOURCE_DIR> && make -j CC=${CMAKE_C_COMPILER} CFLAGS=${CFLAGS} LDFLAGS=${LDFLAGS},
+# which use only flags for Lua build, which were explicitly
+# declared earlier, so we need to add `-g` to CFLAGS by ourselves.
+# See [1].
+#
+# 1. https://github.com/ligurio/lua-c-api-tests/pull/6#discussion_r1185003511
 if (CMAKE_BUILD_TYPE STREQUAL "Debug")
-  set(LDFLAGS "${LDFLAGS} ${CMAKE_C_FLAGS_DEBUG}")
-endif (CMAKE_BUILD_TYPE STREQUAL "Debug")
+  AppendFlags(LDFLAGS ${CMAKE_C_FLAGS_DEBUG})
+endif()
 
 if (ENABLE_ASAN)
-  set(LDFLAGS "${LDFLAGS} -fsanitize=address")
-endif (ENABLE_ASAN)
+  AppendFlags(LDFLAGS -fsanitize=address)
+endif()
 
 if (ENABLE_UBSAN)
-  set(LDFLAGS "${LDFLAGS} -fsanitize=undefined")
-endif (ENABLE_UBSAN)
+  AppendFlags(LDFLAGS -fsanitize=undefined)
+endif()
 
 if (ENABLE_COV)
-  set(LDFLAGS "${LDFLAGS} -fprofile-instr-generate -fcoverage-mapping")
-endif (ENABLE_COV)
+  AppendFlags(LDFLAGS -fprofile-instr-generate -fcoverage-mapping)
+endif()
 
 set(DEFAULT_RUNS_NUMBER 5)
 
@@ -71,13 +80,13 @@ function(create_test)
   target_link_libraries(${test_name} PUBLIC fuzzer_config ${FUZZ_LIBRARIES} ${LUA_LIBRARIES} ${LDFLAGS})
   target_include_directories(${test_name} PRIVATE ${LUA_INCLUDE_DIR})
   target_compile_options(${test_name} PRIVATE -Wall -Wextra -Wpedantic -Wno-unused-parameter -g)
-  add_dependencies(${test_name} ${LUA_TARGET})
+  add_dependencies(${test_name} ${LUA_LIBRARIES})
   string(REPLACE "_test" "" test_prefix ${test_name})
   set(LIBFUZZER_OPTS "${LIBFUZZER_OPTS} -artifact_prefix=${test_name}_")
-  if (USE_LUAJIT AND (${test_name} STREQUAL "lua_dump_test"))
+  if (IS_LUAJIT AND (${test_name} STREQUAL "lua_dump_test"))
     set(LIBFUZZER_OPTS "${LIBFUZZER_OPTS} -only_ascii=1")
   endif ()
-  if (USE_LUAJIT AND (${test_name} STREQUAL "lua_load_test"))
+  if (IS_LUAJIT AND (${test_name} STREQUAL "lua_load_test"))
     set(LIBFUZZER_OPTS "${LIBFUZZER_OPTS} -only_ascii=1")
   endif ()
   set(dict_path ${PROJECT_SOURCE_DIR}/corpus/${test_name}.dict)
@@ -96,14 +105,14 @@ function(create_test)
     set_tests_properties(${test_name} PROPERTIES
       ENVIRONMENT "ASAN_OPTIONS='detect_invalid_pointer_pairs=2'"
     )
-  endif (USE_LUA)
+  endif()
   set_tests_properties(${test_name} PROPERTIES
     LABELS capi
   )
 
-  if (USE_LUAJIT)
+  if (IS_LUAJIT)
     target_compile_definitions(${test_name} PUBLIC LUAJIT)
-  endif (USE_LUAJIT)
+  endif()
 endfunction()
 
 # These Lua C functions are unsupported by LuaJIT.
@@ -121,7 +130,7 @@ list(APPEND LUAJIT_BLACKLIST_TESTS "luaL_loadstring_test")
 file(GLOB tests LIST_DIRECTORIES false ${CMAKE_CURRENT_SOURCE_DIR} *.c *.cc)
 foreach(filename ${tests})
   get_filename_component(test_name ${filename} NAME_WE)
-  if (USE_LUAJIT AND (${test_name} IN_LIST LUAJIT_BLACKLIST_TESTS))
+  if (IS_LUAJIT AND (${test_name} IN_LIST LUAJIT_BLACKLIST_TESTS))
     continue()
   endif ()
   if ((${test_name} IN_LIST BLACKLIST_TESTS))
@@ -134,6 +143,6 @@ endforeach()
 
 include(ProtobufMutator)
 add_subdirectory(luaL_loadbuffer_proto)
-if(USE_LUAJIT)
+if(IS_LUAJIT)
   add_subdirectory(ffi_cdef_proto)
 endif ()