The `pickDataDirectory()` function was calling `exit(0)` to quit
the application when the user closes the dialog without choosing
a data directory.
This is a bad idea because a background thread is created (to
check free space on the drive of the currently selected datadir).
The thread is not stopped and unwound properly, resulting in a potential
race condition somewhere deep in Qt.
So replace the `exit()` by a boolean return value, and let the
stack unwind normally.
QT_NO_KEYWORDS prevents Qt from defining the `foreach`, `signals`,
`slots` and `emit` macros.
Avoid overlap between Qt macros and boost - for example #undef hackiness
in #6421.
Changes for the datadir chooser have made it impossible to specify
the network (testnet/regtest) in the configuration file for the GUI.
Reorganize the initialization sequence to make this possible again.
- Moves the "datadir" QSetting so that is no longer dependent on the
network-specific application name (doing otherwise would create a
chicken-and-egg problem).
- Re-initialize translations after choosing network. There may be a
different language configured in network-specific settings
(slim chance, but handle it for sanity).
Fixes point 1 of #3840.
Use misc methods of avoiding unnecesary header includes.
Replace int typedefs with int##_t from stdint.h.
Replace PRI64[xdu] with PRI[xdu]64 from inttypes.h.
Normalize QT_VERSION ifs where possible.
Resolve some indirect dependencies as direct ones.
Remove extern declarations from .cpp files.
- it was possible to trigger an infinite loop in FreespaceChecker::check() by
simply removing the drive letter on Windows (which leads to an infinite
loop in the FreespaceChecker thread)
- this was caused by not checking if we make progress with
parentDir.parent_path()
This adds an introduction screen that is shown when the client is first
started in which the user can choose a data directory.
It is also possible to force the intro screen to appear using command
line argument `-choosedatadir`.
The user is warned that the client will download and store 10Gb of data.
The intro screen shows how much space is available on the device that
contains the chosen directory and warns if this is less than the 10Gb.
To make it possible to translate the introduction dialog, the initialization
sequence is changed so that translations are
loaded before the data directory. This has the by-effect that it is
no longer possible to specify a language in bitcoin.conf inside the data
directory.
