tests: Add eu-search tests

tests: Add eu-search tests

        * tests/eu_search_cfi.c: New file.
        * tests/eu_search_die.c: New file.
        * tests/eu_search_lines.c: New file.
        * tests/eu_search_macros.c: New file.
        * tests/run-eu-search-tests.sh: New test.
        * tests/Makefile.am: Add USE_LOCKS condition for -pthread.
        (check_PROGRAMS): Add eu_search_cfi, eu_search_die,
        eu_search_lines, and eu_search_macros.
        (TESTS): Add run-eu-search-tests.sh
        (eu_search_cfi_LDADD): New variable.
        (eu_search_die_LDADD): New variable.
        (eu_search_lines_LDADD): New variable.
        (eu_search_macros_LDADD): New variable.
        (eu_search_cfi_LDFLAGS): New variable.
        Add -pthread if USE_LOCKS is not defined.
        (eu_search_die_LDFLAGS): Likewise.
        (eu_search_lines_LDFLAGS): Likewise.
        (eu_search_macros_LDFLAGS): Likewise.

Signed-off-by: Heather S. McIntyre <hsm2@rice.edu>
Signed-off-by: Mark Wielaard <mark@klomp.org>