workaround for bug in mkmf

works-around a known bug in mkmf, which was resolved in
https://bugs.ruby-lang.org/projects/ruby-trunk/repository/revisions/39717

Since the current Windows Ruby distribution doesn't include this fix yet,
we work around it by detecting whether mkmf is functioning properly or
not, and fixing it if it's not. This behavior will degrade gracefully if
the user is running a version of mkmf with the fix.
Add type checks and GC guards before accessing the query options hash in the result object. See #321.
Merge pull request #393 from monban/mkmf-workaround

workaround for bug in mkmf
Merge pull request #346 from sodabrew/gc_guard_hash_dup

Per #321 use RB_GC_GUARD around rb_hash_dup
Add Client#query_info that calls mysql_info.

The function is really useful if you want to retrieve the result of the LOAD
DATA INFILE command.
Parse query_info to a hash
Merge pull request #395 from sodabrew/libc_query_info

Add Client#query_info that calls mysql_info.
protect around rb_intern3
try building on rbx again
really need to rethink this test
Merge branch 'master' into rb_intern3-fix
Merge pull request #398 from brianmario/rb_intern3-fix

Check for existence of rb_intern3 to try and get building on RBX again
add a test console
Merge pull request #397 from brianmario/add-console

Add a test console
blah
Merge branch 'master' into 0.2.x
bump version for 0.2.19 release