extract igmp into its own static library

CMakeLists.txt

@@ -8,12 +8,12 @@ add_subdirectory(eth)
 add_subdirectory(ipv4)
 add_subdirectory(arp)
 add_subdirectory(icmp)
+add_subdirectory(igmp)
 
 add_library(limen STATIC
     src/dispatch.cpp
     src/flash.cpp
     src/handlers.cpp
-    src/igmp.cpp
     src/test_handlers.cpp
     src/udp.cpp
 )
@@ -33,6 +33,7 @@ target_link_libraries(limen PUBLIC
     ipv4
     arp
     icmp
+    igmp
     pico_stdlib
     pico_sha256
 )

igmp/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_library(igmp STATIC igmp.cpp)
+
+target_include_directories(igmp PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+
+target_compile_options(igmp PRIVATE -Wall -Wextra -Wno-unused-parameter)
+
+target_link_libraries(igmp PUBLIC
+    util
+    eth
+    ipv4
+)