libpam: Fix build with LLD linker

LLD is strict about versioned symbols unlike BFD linker, it flags
undefined ones, Allow undefined symbols like BFD linker

Fixes
| riscv64-yoe-linux-ld.lld: error: version script assignment of 'global' to symbol 'pam_sm_acct_mgmt' failed: symbol not defined
| riscv64-yoe-linux-ld.lld: error: version script assignment of 'global' to symbol 'pam_sm_chauthtok' failed: symbol not defined
| riscv64-yoe-linux-ld.lld: error: version script assignment of 'global' to symbol 'pam_sm_close_session' failed: symbol not defined
| riscv64-yoe-linux-ld.lld: error: version script assignment of 'global' to symbol 'pam_sm_open_session' failed: symbol not defined
| riscv64-yoe-linux-clang: error: linker command failed with exit code 1 (use -v to see invocation)

(From OE-Core rev: a53fddbb99dc746439b5b2adfb7f747ba25a856f)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-extended/pam/libpam_1.7.1.bb

@@ -30,6 +30,8 @@ DEPENDS = "bison-native flex-native libxml2-native virtual/crypt"
 
 EXTRA_OEMESON = "-Ddocs=disabled -Dsecuredir=${base_libdir}/security"
 
+LDFLAGS += "${@bb.utils.contains('DISTRO_FEATURES', 'ld-is-lld', ' -Wl,--undefined-version', '', d)}"
+
 S = "${UNPACKDIR}/Linux-PAM-${PV}"
 
 inherit meson gettext pkgconfig systemd ptest github-releases