Build.sh fails, looks like on gtp5g

Dear free5gc support,
Would u pls help:

Build the free5GC core and upf:

  1. cd $GOPATH/src/free5gc
  2. ./build.sh

it fails with below prompt (and my kernel is 5.0.0-23-generic):

tp5g-genl-pdr.c:738:14: warning: data definition has no type or storage class
EXPORT_SYMBOL(gtp5g_print_pdr);
^
gtp5g-genl-pdr.c:738:15: warning: type defaults to ‘int’ in declaration of ‘gtp5g_print_pdr’ [-Wimplicit-int]
EXPORT_SYMBOL(gtp5g_print_pdr);
^~~~~~~~~~~~~~~
gtp5g-genl-pdr.c:738:15: error: ‘gtp5g_print_pdr’ redeclared as different kind of symbol
gtp5g-genl-pdr.c:600:6: note: previous definition of ‘gtp5g_print_pdr’ was here
void gtp5g_print_pdr(struct gtp5g_pdr *pdr)
^~~~~~~~~~~~~~~
gtp5g-genl-pdr.c:882:14: warning: data definition has no type or storage class
EXPORT_SYMBOL(gtp5g_pdr_find_by_id);
^
gtp5g-genl-pdr.c:882:15: warning: type defaults to ‘int’ in declaration of ‘gtp5g_pdr_find_by_id’ [-Wimplicit-int]
EXPORT_SYMBOL(gtp5g_pdr_find_by_id);
^~~~~~~~~~~~~~~~~~~~
gtp5g-genl-pdr.c:882:15: error: ‘gtp5g_pdr_find_by_id’ redeclared as different kind of symbol
gtp5g-genl-pdr.c:859:19: note: previous definition of ‘gtp5g_pdr_find_by_id’ was here
struct gtp5g_pdr *gtp5g_pdr_find_by_id(int genl_id, struct mnl_socket *nl, struct gtp5g_dev *dev, struct gtp5g_pdr *pdr)
^~~~~~~~~~~~~~~~~~~~
Makefile:454: recipe for target ‘gtp5g.lo’ failed
make[5]: *** [gtp5g.lo] Error 1
Makefile:454: recipe for target ‘gtp5g-genl-pdr.lo’ failed
make[5]: *** [gtp5g-genl-pdr.lo] Error 1
Makefile:469: recipe for target ‘all-recursive’ failed
make[4]: *** [all-recursive] Error 1
Makefile:377: recipe for target ‘all’ failed
make[3]: *** [all] Error 2
lib/gtpv1/CMakeFiles/libgtp5gnl.dir/build.make:60: recipe for target ‘libgtp5gnl/lib/libgtp5gnl.so’ failed
make[2]: *** [libgtp5gnl/lib/libgtp5gnl.so] Error 2
CMakeFiles/Makefile2:178: recipe for target ‘lib/gtpv1/CMakeFiles/libgtp5gnl.dir/all’ failed
make[1]: *** [lib/gtpv1/CMakeFiles/libgtp5gnl.dir/all] Error 2
Makefile:83: recipe for target ‘all’ failed
make: *** [all] Error 2
smartedge@ubuntu-18043:~/go/src/free5gc$

thanks a lot!

issue solved by myself, would you pls close it, thanks.