Cleanup autotools scripts

[NattyNarwhal]

• Assumes PHP's autotools functions are from at least 2005.
• Simplify the search for libraries and includes.
• For PASE, simplify search, and support SG's libdb400 wrapper (used because of AIX loader limitatioons).

Fixes GH-14

[NattyNarwhal]

Two thoughts:

• I don't know what the AIX check is for. It's been there from the beginning.
• The PASE check could be simplified further if we convert all references of the PASE define to __PASE__.

[kadler]

LGTM

[kadler]

Looks like __H_LOCALEDEF prevents inclusion of sys/localedef.h in ctype.h, langinfo.h, and stdlib.h. I have no idea why that would matter, though. Perhaps a workaround for some old bug? Certainly doesn't seem to be a problem when building on PASE, which would have the same issue as AIX.

[NattyNarwhal]

Looking at the 32/64-bit check, could avoid checking the "wrong" one by:

1. what PHP exts do, i.e. ldap:

    AC_CHECK_SIZEOF([long])
    AC_MSG_CHECKING([if we're at 64-bit platform])
    AS_IF([test "$ac_cv_sizeof_long" -eq 4],[
      AC_MSG_RESULT([no])
      PHP_OCI8_IC_LIBDIR_SUFFIX=""
    ],[
      AC_MSG_RESULT([yes])
      PHP_OCI8_IC_LIBDIR_SUFFIX=64
    ])

2. what ibm_db2 does, calling PHP at runtime (might be fragile?):

  AC_MSG_CHECKING(PHP)
  if test `php -r 'echo PHP_INT_SIZE;'` = 8; then
    machine_bits=64
    libDir=lib64
    AC_MSG_RESULT(Detected 64-bit PHP)
  else
    machine_bits=32
    libDir=lib32
    AC_MSG_RESULT(Detected 32-bit PHP)
  fi

[kadler]

Yeah, checking ac_cv_sizeof_long and checking lib32/lib64 as appropriate would be good.