[bug#54619] [PATCH] gnu: lsof: Fix cross-compilation.

[Brian Kubisiak <brian@kubisiak.com>]

Hello Mathieu,

I see the following compiler errors during the build phase when trying
to build with `guix build --target=aarch64-linux-gnu lsof':

dsock.c: In function ‘build_IPstates’:
dsock.c:392:49: error: ‘TCP_ESTABLISHED’ undeclared (first use in this function)
  392 |      (void) enter_IPstate("TCP", "ESTABLISHED", TCP_ESTABLISHED);
      |                                                 ^~~~~~~~~~~~~~~
dsock.c:392:49: note: each undeclared identifier is reported only once for each function it appears in
aarch64-linux-gnu-gcc  -DLINUXV=00000 -DHASNORPC_H -D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE -DLSOF_VSTR=\"0.0.0\"    -O   -c -o usage.o usage.c
dsock.c:393:46: error: ‘TCP_SYN_SENT’ undeclared (first use in this function); did you mean ‘TCP_SYNCNT’?
  393 |      (void) enter_IPstate("TCP", "SYN_SENT", TCP_SYN_SENT);
      |                                              ^~~~~~~~~~~~
      |                                              TCP_SYNCNT
dsock.c:394:46: error: ‘TCP_SYN_RECV’ undeclared (first use in this function)
  394 |      (void) enter_IPstate("TCP", "SYN_RECV", TCP_SYN_RECV);
      |                                              ^~~~~~~~~~~~
dsock.c:395:47: error: ‘TCP_FIN_WAIT1’ undeclared (first use in this function)
  395 |      (void) enter_IPstate("TCP", "FIN_WAIT1", TCP_FIN_WAIT1);
      |                                               ^~~~~~~~~~~~~
dsock.c:396:47: error: ‘TCP_FIN_WAIT2’ undeclared (first use in this function)
  396 |      (void) enter_IPstate("TCP", "FIN_WAIT2", TCP_FIN_WAIT2);
      |                                               ^~~~~~~~~~~~~
dsock.c:397:47: error: ‘TCP_TIME_WAIT’ undeclared (first use in this function); did you mean ‘TCP_TIMESTAMP’?
  397 |      (void) enter_IPstate("TCP", "TIME_WAIT", TCP_TIME_WAIT);
      |                                               ^~~~~~~~~~~~~
      |                                               TCP_TIMESTAMP
dsock.c:398:43: error: ‘TCP_CLOSE’ undeclared (first use in this function); did you mean ‘TCP_CORK’?
  398 |      (void) enter_IPstate("TCP", "CLOSE", TCP_CLOSE);
      |                                           ^~~~~~~~~
      |                                           TCP_CORK
dsock.c:399:48: error: ‘TCP_CLOSE_WAIT’ undeclared (first use in this function)
  399 |      (void) enter_IPstate("TCP", "CLOSE_WAIT", TCP_CLOSE_WAIT);
      |                                                ^~~~~~~~~~~~~~
dsock.c:400:46: error: ‘TCP_LAST_ACK’ undeclared (first use in this function); did you mean ‘TCP_FLAG_ACK’?
  400 |      (void) enter_IPstate("TCP", "LAST_ACK", TCP_LAST_ACK);
      |                                              ^~~~~~~~~~~~
      |                                              TCP_FLAG_ACK
dsock.c:401:44: error: ‘TCP_LISTEN’ undeclared (first use in this function); did you mean ‘TCP_FASTOPEN’?
  401 |      (void) enter_IPstate("TCP", "LISTEN", TCP_LISTEN);
      |                                            ^~~~~~~~~~
      |                                            TCP_FASTOPEN
dsock.c:402:45: error: ‘TCP_CLOSING’ undeclared (first use in this function); did you mean ‘POF_CLOSING’?
  402 |      (void) enter_IPstate("TCP", "CLOSING", TCP_CLOSING);
      |                                             ^~~~~~~~~~~
      |                                             POF_CLOSING
dsock.c: In function ‘get_tcpudp’:
dsock.c:2998:20: error: ‘TCP_ESTABLISHED’ undeclared (first use in this function)
 2998 |   if (tp->state == TCP_ESTABLISHED) {
      |                    ^~~~~~~~~~~~~~~
dsock.c: In function ‘get_unix’:
dsock.c:3527:64: error: ‘UINT32_MAX’ undeclared (first use in this function); did you mean ‘UINT_MAX’?
 3527 |      ||  (ty = (uint32_t)strtoul(fp[4], &ep, 16)) == (uint32_t)UINT32_MAX
      |                                                                ^~~~~~~~~~
      |                                                                UINT_MAX
make: *** [<builtin>: dsock.o] Error 1
make: *** Waiting for unfinished jobs....

Checking the build log, I see the following error:

Testing C library type with aarch64-linux-gnu-gcc ... ./Configure: line 2922: ./lsof_Configure_tmp_26.x: cannot execute binary file: Exec format error
done
Cannot determine C library type; assuming it is not glibc.

So I believe the compiler errors are caused by attempting to build
with glibc without adding glibc-specific build flags. The root cause
of this is that the c library detection in lsof builds and runs a
small program in order to see if it's using glibc. Since it is
building this with the cross-compiler, the resulting binary (usually)
won't be able to run on the host.

If you have binfmt_misc + qemu set up on your machine, you may not see
this error.

The solution is to point LINUX_CONF_CC at the build machine's compiler
instead of using the cross compiler for this step, which should build
and execute the test program natively.

Thanks,
Brian