build-system: stop looking for %ms and %as

Looks like those specifiers haven't been used since 6c9ab254aefb6ce7e0e
(where sscanf was removed) was merged. This should help to get
util-linux to compile with MSan. Currently it's failing with
```
...
configure: error: libmount selected, but required scanf string alloc modifier not available
...
configure:20240: ./conftest
==116617==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x496fd6 in main /home/vagrant/util-linux/conftest.c:171:6
    #1 0x7f5eb85ea1a2 in __libc_start_main (/lib64/libc.so.6+0x271a2)
    #2 0x41c2cd in _start (/home/vagrant/util-linux/conftest+0x41c2cd)

SUMMARY: MemorySanitizer: use-of-uninitialized-value /home/vagrant/util-linux/conftest.c:171:6 in main
Exiting
configure:20240: $? = 77
...
configure:20265: $? = 0
configure:20265: ./conftest
MemorySanitizer: bad pointer 0x000000496e60
==116627==MemorySanitizer CHECK failed: /builddir/build/BUILD/compiler-rt-9.0.1.src/lib/msan/../sanitizer_common/sanitizer_allocator_secondary.h:177 "((IsAligned(reinterpret_cast<uptr>(p), page_size_))) != (0)" (0x0, 0x0)
    #0 0x41d1d8 in MsanCheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) (/home/vagrant/util-linux/conftest+0x41d1d8)
    #1 0x484e1e in __sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) (/home/vagrant/util-linux/conftest+0x484e1e)
    #2 0x42066c in __msan::MsanDeallocate(__sanitizer::StackTrace*, void*) (/home/vagrant/util-linux/conftest+0x42066c)
    #3 0x424bc9 in free (/home/vagrant/util-linux/conftest+0x424bc9)
    #4 0x496fae in main /home/vagrant/util-linux/conftest.c:173:2
    #5 0x7f2245f311a2 in __libc_start_main (/lib64/libc.so.6+0x271a2)
    #6 0x41c2cd in _start (/home/vagrant/util-linux/conftest+0x41c2cd)

configure:20265: $? = 77
configure: program exited with status 77
...
| }
configure:22568: result: no
configure:22926: error: libmount selected, but required scanf string alloc modifier not available
```

Signed-off-by: Evgeny Vereshchagin <evvers@ya.ru>
2 files changed