* configure.ac: Don't define ENABLE_CHECKING whenever
--enable-checking is seen, instead use similar --enable-checking=yes
vs. --enable-checking=release default as gcc/ subdir has and
define ENABLE_CHECKING if ENABLE_CHECKING is defined in gcc/.
Define ENABLE_VALGRIND_CHECKING if requested.
* lex.c (new_buff): If ENABLE_VALGRIND_CHECKING, put _cpp_buff
struct first in the allocated buffer and result->base after it.
(_cpp_free_buff): If ENABLE_VALGRIND_CHECKING, free buff itself
instead of buff->base.
* config.in: Regenerated.
* configure: Regenerated.
From-SVN: r196333
1a80db971d