libsysprof-capture: Use C11 types instead of GLib types

This is an almost entirely mechanical* conversion from (for example)
`gint` → `int`, `guint8` → `uint8_t`, etc.

It is not entirely complete, as many GLib functions are still used in
libsysprof-capture, which necessitate some use of GLib types.

It also avoids renaming `gboolean` → `bool` as that’s a slightly more
controversial change which will happen in the following commit.

*Code was manually realigned afterwards.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Helps: #40

src/libsysprof-capture/sysprof-capture-util-private.h

@@ -84,7 +84,7 @@ ssize_t _sysprof_pwrite      (int         fd,
 ssize_t _sysprof_write       (int         fd,
                               const void *buf,
                               size_t      count);
-gint32  _sysprof_getpid      (void);
+int32_t _sysprof_getpid      (void);
 ssize_t _sysprof_sendfile    (int         out_fd,
                               int         in_fd,
                               off_t      *offset,