Fix strict aliasing problems or add -fno-strict-aliasing

Fix strict aliasing problems or add -fno-strict-aliasing

Create a new CFLAGS_NOSTRICT Autoconf substitution variable which
is set to -fno-strict-aliasing if we're using gcc to compile.  Add
@CFLAGS_NOSTRICT@ to the C compiler flags for source files that have
significant strict-aliasing issues.

Fix minor strict-aliasing issues elsewhere in the tree by using memcpy
to copy the data into a properly typed variable.

Change-Id: I43afdb5e33e06cb249b7db385a65daf8d2133a19
Reviewed-on: http://gerrit.openafs.org/1617
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>