New Intel OneAPI compiler names

New Intel OneAPI compiler names

Reported: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=78817

* libltdl/libltdl/lt__alloc.h: Change FREE and MEMREASSIGN macros for
  -Wcompound-token-split-by-macro.
* libltdl/libltdl/lt_system.h: Change LT_STMT_START and LT_STMT_END
  macros for -Wcompound-token-split-by-macro.
* libltdl/loaders/loadlibrary.c: Add support for icx, icpx, ifx.
* libltdl/ltdl.c: Fixes for Clang.
* m4/libtool.m4: Add support for icx, icpx, and ifx.
* NEWS: Update.