DynamicLoader+LibC+LibTimeZone: Include LibTimeZone sources in LibC

LibTimeZone will be needed directly within LibC for functions such as
localtime(). This change adds LibTimeZone directly within LibC, so that
LibTimeZone isn't its own .so library anymore.

LibTimeZone itself is compiled as an object library to make it easier to
give it generator-specific compilation flags.

Userland/DynamicLoader/CMakeLists.txt

@@ -45,5 +45,6 @@ elseif (CMAKE_CXX_COMPILER_ID MATCHES "Clang$")
     target_link_libraries(Loader.so PRIVATE clang_rt.builtins)
 endif ()
 
+target_link_libraries(Loader.so PRIVATE LibTimeZone)
 target_link_options(Loader.so PRIVATE LINKER:--no-dynamic-linker)
 install(TARGETS Loader.so RUNTIME DESTINATION usr/lib/)

Userland/Libraries/LibC/CMakeLists.txt

@@ -130,7 +130,7 @@ set(SOURCES ${LIBC_SOURCES} ${AK_SOURCES} ${ELF_SOURCES} ${ASM_SOURCES})
 set_source_files_properties(stdio.cpp PROPERTIES COMPILE_FLAGS "-fno-builtin-fputc -fno-builtin-fputs -fno-builtin-fwrite")
 
 add_library(LibCStaticWithoutDeps STATIC ${SOURCES})
-target_link_libraries(LibCStaticWithoutDeps ssp)
+target_link_libraries(LibCStaticWithoutDeps ssp LibTimeZone)
 add_dependencies(LibCStaticWithoutDeps LibM LibSystem LibUBSanitizer)
 
 add_custom_target(LibCStatic
@@ -154,7 +154,7 @@ set_property(
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -nolibc")
 serenity_libc(LibC c)
 add_dependencies(LibC crti crt0 crt0_shared crtn)
-target_link_libraries(LibC ssp system)
+target_link_libraries(LibC ssp system LibTimeZone)
 
 # We mark LibCStatic as a dependency of LibC because this triggers the build of the LibCStatic target
 add_dependencies(LibC LibM LibSystem LibCStatic)

Userland/Libraries/LibTimeZone/CMakeLists.txt

@@ -5,6 +5,5 @@ set(SOURCES
     ${TIME_ZONE_DATA_SOURCES}
 )
 
-serenity_lib(LibTimeZone timezone)
-target_link_libraries(LibTimeZone LibCore)
+add_library(LibTimeZone OBJECT ${SOURCES})
 target_compile_definitions(LibTimeZone PRIVATE ENABLE_TIME_ZONE_DATA=$<BOOL:${ENABLE_TIME_ZONE_DATABASE_DOWNLOAD}>)