Can you include the portion of config.log from the line containing:

checking whether C compiler accepts -fvisibility=hidden

up to and including the resule: line?  It sounds like the IBM XL C compiler isn't returning an error when the test is run.

sure

configure:20393: checking whether C compiler accepts -fvisibility=hidden
configure:20412: cc -qlanglvl=extc89 -c -g  -fvisibility=hidden  conftest.c >&5
configure:20412: $? = 0
configure:20421: result: yes

what would be the content of conftest.c to manually test this command?
cc -qlanglvl=extc89 -c -g  -fvisibility=hidden  conftest.c


Best regards,

Yannick Bergeron

configure just uses an empty main() for the test.  E.g.

int
main()
{
  return 0;
}

If we can't rely on that test working I can just restrict it to gcc and workalikes.

# cat conftest.c 
int
main()
{
  return 0;
}

# cc -qlanglvl=extc89 -c -g  -fvisibility=hidden  conftest.c
root@aix53tst ==> echo $?
0

# ls conftest*
-rw-------    1 root     system           28 Jan 10 14:46 conftest.c
-rw-------    1 root     system         1431 Jan 10 14:46 conftest.o


ok... it compiles this way...
but if I try that way:
# pwd
/usr/src/sudo-1.8.6p3/compat

# cat conftest.c
int
main()
{
  return 0;
}

# cc -qlanglvl=extc89 -I../include -I.. -I..  -g -fvisibility=hidden  -D_ALL_SOURCE -D_LINUX_SOURCE_COMPAT ./conftest.c -o conftest
ld: 0706-005 Cannot find or open file: visibility=hidden
        ld:fopen(): A file or directory in the path name does not exist.

# echo $?
255



Best regards,

Yannick Bergeron

I think that the use of "-c" in the test make it passes
As "-c" is not used at the compilation, it fails

         -c     Instructs the compiler to pass source files to the
                compiler only. The compiled source files are not
                sent to the linker. This option produces an object
                file, file_name.o, for each valid source file.

         -f<file_name>
                Names a file to store a list of object files for
                the compiler to pass to the linker. The <file_name>
                file should contain only the names of object files.
                There should be one object file per line.

# cat conftest.c                                         
int
main()
{
  return 0;
}

# cc -qlanglvl=extc89 -g  -fvisibility=hidden  conftest.c
ld: 0706-005 Cannot find or open file: visibility=hidden
        ld:fopen(): A file or directory in the path name does not exist.

# echo $?
255

# cc -qlanglvl=extc89 -g conftest.c                      

# echo $?
0

Fixed in sudo 1.8.6p4.