Makefile: fix broken kerberos build in linux

[badis]

Possibly related to issues: #38841 and #39480.
I have enabled building of shared libraries for kerberos in linux(ubuntu 18.04) to avoid this kind of errors:

/home/badis/go/src/github.com/cockroachdb/cockroach/c-deps/krb5/src/lib/crypto/builtin/aes/iaesx64.s:791: Error: junk at end of line, first unrecognized character is `%'
/home/badis/go/src/github.com/cockroachdb/cockroach/c-deps/krb5/src/lib/crypto/builtin/aes/iaesx64.s:792: Error: no such instruction: `section .note.GNU-stack noalloc noexec nowrite progbits'
/home/badis/go/src/github.com/cockroachdb/cockroach/c-deps/krb5/src/lib/crypto/builtin/aes/iaesx64.s:793: Error: junk at end of line, first unrecognized character is `%'
/home/badis/go/src/github.com/cockroachdb/cockroach/c-deps/krb5/src/lib/crypto/builtin/aes/iaesx64.s:794: Error: junk at end of line, first unrecognized character is `%'
/home/badis/go/src/github.com/cockroachdb/cockroach/c-deps/krb5/src/lib/crypto/builtin/aes/iaesx64.s:795: Error: no such instruction: `section .note.GNU-stack noalloc noexec nowrite progbits'
/home/badis/go/src/github.com/cockroachdb/cockroach/c-deps/krb5/src/lib/crypto/builtin/aes/iaesx64.s:796: Error: junk at end of line, first unrecognized character is `%'
/home/badis/go/src/github.com/cockroachdb/cockroach/c-deps/krb5/src/lib/crypto/builtin/aes/iaesx64.s:797: Error: junk at end of line, first unrecognized character is `%'
/home/badis/go/src/github.com/cockroachdb/cockroach/c-deps/krb5/src/lib/crypto/builtin/aes/iaesx64.s:798: Error: no such instruction: `section .note.GNU-stack noalloc noexec nowrite progbits'
/home/badis/go/src/github.com/cockroachdb/cockroach/c-deps/krb5/src/lib/crypto/builtin/aes/iaesx64.s:799: Error: junk at end of line, first unrecognized character is `%'
<builtin>: recipe for target 'iaesx64.o' failed
make[5]: *** [iaesx64.o] Error 1
Makefile:1139: recipe for target 'all-recurse' failed
make[4]: *** [all-recurse] Error 1
Makefile:1107: recipe for target 'all-recurse' failed
make[3]: *** [all-recurse] Error 1
Makefile:992: recipe for target 'all-recurse' failed
make[2]: *** [all-recurse] Error 1
Makefile:1533: recipe for target 'all-recurse' failed
make[1]: *** [all-recurse] Error 1
Makefile:719: recipe for target '/home/badis/go/native/x86_64-linux-gnu/krb5/lib/libgssapi_krb5.a' failed
make: *** [/home/badis/go/native/x86_64-linux-gnu/krb5/lib/libgssapi_krb5.a] Error 2

Release note (bug fix): Fixed a Makefile bug that would prevent building shared libraries of kerberos in linux and thus prevent building CockroachDB from sources.

[cockroach-teamcity]

This change is 

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

Badis Merabet seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[benesch]

This doesn't seem like the right way to fix the issue, I'm afraid. If it works for your use case, great! But the cockroach build system is meant to produce a completely statically linked binary (save for libc, if you're using a system that does not support statically linking libc). The fix which @knz proposes in #39480, of overriding the unworkable configure check, seems like the way to go.

[knz]

@badis can you have a look at #48132 and see if something similar applies to you here?