Patch #3. This patch removes the following:

HAVE_SETENV - always true
HAVE_DECL_SHM_HUGETLB - use HAVE_LARGE_PAGES instead
HUGETLB_USE_PROC_MEMINFO - use HAVE_LARGE_PAGES instead
HAVE_LARGE_PAGE_OPTION - use HAVE_LARGE_PAGES || HAVE_SOLARIS_LARGE_PAGES instead
HAVE_RWLOCK_T - never used
HAVE_DECL_MHA_MAPSIZE_CA - use HAVE_SOLARIS_LARGE_PAGES instead
HAVE_SYS_IPC_H - always true (where used)
HAVE_SYS_SHM_H - always true (where used)

Removed _MSC_VER checks where they are not relevant as we require Visual Studio 2010
(which has _MSC_VER = 1600). Also added CMake check which aborts configuration if
an older version of Visual Studio is used.

Removed HAVE_PREAD checks where they are not relevant. HAVE_PREAD is always true
for non-Windows supported platforms (POSIX).