bitmanipulation: fix undefined behavior in bit shift in getbe32 OSS-Fuzz caught this in its ubsan mode[0]. I'm not worried about a security issue here because in practice this should work out the way we naively expected, we're just making things explicit to the compiler with the casts. 0: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=8876 Differential Revision: https://phab.mercurial-scm.org/D3729

lazymanifest: don't crash when out of memory (issue5916) self->lines can be NULL if we failed to allocate memory for it.

cext: stop worrying and love the free(NULL) There is no need to check for a NULL pointer before calling free since free(NULL) is defined by C standards as a no-op. Lots of software relies on this behavior so it is completely safe to call even on the most obscure of systems.