support: clamp RLIMIT_MEMLOCK to size_t

On 32-bit systems we build with _FILE_OFFSET_BITS=64 (see CMakeLists.txt),
which makes rlim_t 64-bit when building against glibc (see bits/resource.h).
Since size_t could be 32-bit, clamp RLIMIT_MEMLOCK to
std::numeric_limits<size_t>::max() in PosixLockedPageAllocator::GetLimit().

Co-authored-by: Luke Dashjr <luke-jr+git@utopios.org>

Author: Sjors

src/support/lockedpool.cpp

@@ -262,7 +262,8 @@ size_t PosixLockedPageAllocator::GetLimit()
 #ifdef RLIMIT_MEMLOCK
     struct rlimit rlim;
     if (getrlimit(RLIMIT_MEMLOCK, &rlim) == 0) {
-        if (rlim.rlim_cur != RLIM_INFINITY) {
+        if (rlim.rlim_cur != RLIM_INFINITY &&
+            std::cmp_less_equal(rlim.rlim_cur, static_cast<rlim_t>(std::numeric_limits<size_t>::max()))) {
             return rlim.rlim_cur;
         }
     }