[review v5] Use libxxhash for hashing, if present

[Tom Tromey (Code Review)]

Tom Tromey has posted comments on this change.

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/39
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Patch Set 5:

(1 comment)

Thank you.  This looks good to me, though I had one suggestion
for the configure change.

https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/39/5/gdb/configure.ac 
File gdb/configure.ac:

https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/39/5/gdb/configure.ac@2224 
PS5, Line 2224: AC_MSG_CHECKING([whether to use xxhash])
              : AC_MSG_RESULT([$with_xxhash])
              : 
              : if test "x$with_xxhash" != "xno"; then
              :   AC_LIB_HAVE_LINKFLAGS([xxhash], [],
              : 			[#include <xxhash.h>],
              : 			[XXH32("foo", 3, 0);
              : 			])
              :   if test "$HAVE_XXHASH" != yes; then
              :      if test "$with_xxhash" = yes; then
              :        AC_MSG_ERROR([xxhash is missing or unusable])
              :      fi
              :   fi
              : fi
I think the `auto` case here should not error if the library is missing.
Instead it should just switch to `no`.  This also means that the
`AC_MSG_RESULT` should be moved lower.