pagemap-cache: Fix compilation on PI, v2

pagemap-cache.c: In function ‘pmc_init’:
pagemap-cache.c:35:20: error: comparison of distinct pointer types lacks a cast [-Werror]
pagemap-cache.c: In function ‘pmc_fill_cache’:
pagemap-cache.c:72:2: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 3 has type ‘uint64_t’ [-Werror=format]
pagemap-cache.c:72:2: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 4 has type ‘uint64_t’ [-Werror=format]
pagemap-cache.c:72:2: error: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 5 has type ‘size_t’ [-Werror=format]
pagemap-cache.c:89:3: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 3 has type ‘uint64_t’ [-Werror=format]
pagemap-cache.c:89:3: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 4 has type ‘uint64_t’ [-Werror=format]
pagemap-cache.c:100:4: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 3 has type ‘uint64_t’ [-Werror=format]
pagemap-cache.c:100:4: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 4 has type ‘uint64_t’ [-Werror=format]
pagemap-cache.c: In function ‘pmc_get_map’:
pagemap-cache.c:136:3: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 6 has type ‘uint64_t’ [-Werror=format]
pagemap-cache.c:136:3: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 7 has type ‘uint64_t’ [-Werror=format]

Reported-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
posix-timer: take into account that sival_ptr can be NULL (v3)

ID: 0
signal: 26/          (null)
notify: signal/pid.5954
ClockID: 1

fscanf "%p" doesn't handle "(null)".

https://bugzilla.openvz.org/show_bug.cgi?id=2894

v2: make the original scanf be %d/%s and then additionally
    parse the obtained string
v3: don't use strstr

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>