Use system's crc32c if found

--- tg_owt-10d5f4bf77333ef6b43516f90d2ce13273255f41.orig/CMakeLists.txt
+++ tg_owt-10d5f4bf77333ef6b43516f90d2ce13273255f41/CMakeLists.txt
@@ -147,7 +147,6 @@
 
 target_link_libraries(tg_owt
 PRIVATE
-    tg_owt::libcrc32c
     tg_owt::libpffft
     tg_owt::librnnoise
     tg_owt::libsrtp
@@ -185,6 +184,7 @@
 link_libabsl(tg_owt)
 link_libopenh264(tg_owt)
 link_libvpx(tg_owt)
+link_crc32c(tg_owt)
 
 if (TG_OWT_BUILD_AUDIO_BACKENDS AND (UNIX AND NOT APPLE))
     link_libalsa(tg_owt)
@@ -2599,7 +2599,6 @@
 
 set(export_targets
     ${tg_owt_export}
-    libcrc32c
     libpffft
     librnnoise
     libsrtp
@@ -2617,6 +2616,9 @@
 if (NOT LIBOPENH264_FOUND)
     list(APPEND export_targets libopenh264)
 endif()
+if (NOT Crc32c_FOUND)
+    list(APPEND export_targets libcrc32c)
+endif()
 
 export(
     TARGETS ${export_targets}
--- tg_owt-10d5f4bf77333ef6b43516f90d2ce13273255f41.orig/cmake/external.cmake
+++ tg_owt-10d5f4bf77333ef6b43516f90d2ce13273255f41/cmake/external.cmake
@@ -166,6 +166,20 @@
     endif()
 endfunction()
 
+# crc32c
+function(link_crc32c target_name)
+    if (TG_OWT_PACKAGED_BUILD)
+        find_package(Crc32c)
+        set(Crc32c_FOUND ${Crc32c_FOUND} PARENT_SCOPE)
+        if (Crc32c_FOUND)
+            target_link_libraries(${target_name} PRIVATE Crc32c::crc32c)
+        endif()
+    endif()
+    if (NOT Crc32c_FOUND)
+        target_link_libraries(${target_name} PRIVATE tg_owt::libcrc32c)
+    endif()
+endfunction()
+
 function(link_glib target_name)
     find_package(PkgConfig REQUIRED)
     pkg_check_modules(GLIB2 REQUIRED glib-2.0)
--- tg_owt-10d5f4bf77333ef6b43516f90d2ce13273255f41.orig/src/net/dcsctp/packet/crc32c.cc
+++ tg_owt-10d5f4bf77333ef6b43516f90d2ce13273255f41/src/net/dcsctp/packet/crc32c.cc
@@ -11,7 +11,7 @@
 
 #include <cstdint>
 
-#include "third_party/crc32c/src/include/crc32c/crc32c.h"
+#include "crc32c/crc32c.h"
 
 namespace dcsctp {