Add import for linux/can/isotp.h

IsoTp CAN protocol is available since
Kernel v5.10 but several constants
from isotp.h have not found their
way into socket module.

This commit adds that header file if
configure finds it.

Signed-off-by: Patrick Menschel <menschel.p@posteo.de>

Author: Patrick Menschel

Modules/socketmodule.h

@@ -144,6 +144,10 @@ typedef int socklen_t;
 #include <linux/can/bcm.h>
 #endif
 
+#ifdef HAVE_LINUX_CAN_ISOTP_H
+#include <linux/can/isotp.h>
+#endif
+
 #ifdef HAVE_LINUX_CAN_J1939_H
 #include <linux/can/j1939.h>
 #endif

configure

@@ -8406,7 +8406,7 @@ done
 
 
 # On Linux, can.h, can/bcm.h, can/j1939.h, can/raw.h require sys/socket.h
-for ac_header in linux/can.h linux/can/bcm.h linux/can/j1939.h linux/can/raw.h
+for ac_header in linux/can.h linux/can/bcm.h linux/can/j1939.h linux/can/raw.h linux/can/isotp.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_compile "$LINENO" "$ac_header" "$as_ac_Header" "

configure.ac

@@ -2270,7 +2270,7 @@ AC_CHECK_HEADERS(linux/vm_sockets.h,,,[
 ])
 
 # On Linux, can.h, can/bcm.h, can/j1939.h, can/raw.h require sys/socket.h
-AC_CHECK_HEADERS(linux/can.h linux/can/bcm.h linux/can/j1939.h linux/can/raw.h,,,[
+AC_CHECK_HEADERS(linux/can.h linux/can/bcm.h linux/can/j1939.h linux/can/raw.h linux/can/isotp.h,,,[
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
 #endif