Bug 60473

Building 0.15.1 on up to date Debian/sid (with libtasn 2.14 from experimental) I get a testsuite error:
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(SID)ametzler@argenau:/tmp/P11-KIT/p11-kit-0.15.1$ ./common/tests/test-attrs
Segmentation fault
(SID)ametzler@argenau:/tmp/P11-KIT/p11-kit-0.15.1$ gdb ./common/tests/test-attrs
GNU gdb (GDB) 7.4.1-debian
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Reading symbols from /tmp/P11-KIT/p11-kit-0.15.1/common/tests/test-attrs...done.
(gdb) run
Starting program: /tmp/P11-KIT/p11-kit-0.15.1/common/tests/test-attrs
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x0804cd71 in attrs_build (attrs=0x8055670, attrs@entry=0x0, count_to_add=1,
    copy=copy@entry=true,
    generator=generator@entry=0x804b760 <vararg_generator>,
    state=state@entry=0xffffd544) at attrs.c:110
110                     if (!add || add->type == CKA_INVALID)
(gdb) bt
#0  0x0804cd71 in attrs_build (attrs=0x8055670, attrs@entry=0x0,
    count_to_add=1, copy=copy@entry=true,
    generator=generator@entry=0x804b760 <vararg_generator>,
    state=state@entry=0xffffd544) at attrs.c:110
#1  0x0804cf3f in p11_attrs_build (attrs=attrs@entry=0x0) at attrs.c:161
#2  0x0804af5d in test_build_one (tc=0x8055290) at test-attrs.c:71
#3  0x0804e940 in CuTestRun (tc=tc@entry=0x8055290) at cutest/CuTest.c:143
#4  0x0804ef3c in CuSuiteRun (testSuite=testSuite@entry=0x8054120)
    at cutest/CuTest.c:279
#5  0x08049023 in main () at test-attrs.c:605
(gdb)
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