add SystemErrno to Error

[rittneje]

fixes #678

[rittneje]

@mattn @gjrtimmer sqlite3_system_errno was added in SQLite 3.12.0. I guess whatever version you are using in the libsqlite3 tests is older than that. I don't see anywhere in your README that mentions a minimum required version of libsqlite3. How would you like me to proceed?

[coveralls]

Coverage increased (+0.2%) to 50.622% when pulling 4581f04 on rittneje:feature/678-add-system-errno-to-error-struct into d3c6909 on mattn:master.

[rittneje]

@mattn @gjrtimmer I was able to leverage the C pre-processor to work around the version issue.

[gjrtimmer]

@mattn @gjrtimmer sqlite3_system_errno was added in SQLite 3.12.0. I guess whatever version you are using in the libsqlite3 tests is older than that. I don't see anywhere in your README that mentions a minimum required version of libsqlite3. How would you like me to proceed?

The libsqlite3 test is using the library on the Travis CI system. Don't know if we can update to force a specific version.

[gjrtimmer]

@rittneje On first glance, this PR look great.

[mattn]

Sounds good to me.

[gjrtimmer]

@mattn What is the default we are using for merging "Create a Merge Request" of "Squash and merge"

[mattn]

I don't have strong opinion. Feel free to create rule if you want. :)

[rittneje]

@gjrtimmer @mattn Can this be merged?

[rittneje]

ping @mattn

[mattn]

Thanks