devel/crc32c: fix build on big-endian architectures

C++11 compiler is needed:

Target "crc32c" requires the language dialect "CXX11" , but CMake does not
know the compile flags to use to enable it.

Additionally, big-endian code in src/crc32c_read_le.h needs fixing - the value is 64 bits wide, not 32 bits.

PR: 239420
Approved by: amzo1337@gmail.com (maintainer), tcberner (mentor)
Differential Revision: https://reviews.freebsd.org/D21054