autumn cleanup of configure:

autumn cleanup of configure:

1. we now consistently use WXCONFIG_C[PP|XX]_FLAGS instead of a mix of CODE_GEN_FLAGS
   plus tons of ad hoc variables (TOOLCHAIN_DEFS, WX_LARGEFILE_FLAGS, WXDEBUG_DEFINE
   and so on) which could all be simply removed now

2. output more stuff which used to be in CFLAGS only in wx-config output:
 a) pthread options (they are needed for user code compilation too)
 b) -D__STDC__EXT needed under HP-UX, this should finally fix the build there

3. also removed GCC_PRAGMA_FLAGS which is unused any more

4. use consitent naming for a couple of other variables

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@36220 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775