Provide some basic documentation.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

We may want to keep track of the version of libpushover in code (for
ABI/API changes, backwards compatibility, etc.)
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

sbuf is much easier to work with.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

Properly reflect that we're setting the destination token rather than
some random user token.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

I don't want libcurl to output any data to the console. Completely
silence libcurl.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

We don't need libcurl to show status/progress. But we do want libcurl to
fail when there's an error.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

We'll want to store key-value configuration options for each node. These
structures are incomplete, just like the rest of the project. However,
this is a good beginning to what the data is going to look like in
memory.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

Why, oh why, am I making these mistakes? ;)
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

Braino. At least this would've just caused a slow memory leak. Nothing
to see here. Move along. ;)
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

We needs this sanity checking in multiple places, so create a new
function internal to libpushover: `pushover_message_priority_sane`.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

Ensuring sane values for any user-defined input is always a good idea.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

Introduce `pushover_free_ctx` and `pushover_free_message`.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

To prevent UAF bugs, use double indirection to set the pointer to NULL
if the message was dynamically allocated.

In order to know whether to free the pushover_message_t object itself,
add a 64-bit wide flags member to the object.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>