These instances were detected by searching for files that include
AK/Format.h, but don't match the regex:
\\b(CheckedFormatString|critical_dmesgln|dbgln|dbgln_if|dmesgln|FormatBu
ilder|__FormatIfSupported|FormatIfSupported|FormatParser|FormatString|Fo
rmattable|Formatter|__format_value|HasFormatter|max_format_arguments|out
|outln|set_debug_enabled|StandardFormatter|TypeErasedFormatParams|TypeEr
asedParameter|VariadicFormatParams|v_critical_dmesgln|vdbgln|vdmesgln|vf
ormat|vout|warn|warnln|warnln_if)\\b
(Without the linebreaks.)
This regex is pessimistic, so there might be more files that don't
actually use any formatting functions.
Observe that this revealed that Userland/Libraries/LibC/signal.cpp is
missing an include.
In theory, one might use LibCPP to detect things like this
automatically, but let's do this one step after another.
MutexProtected mirrors the identically-named Kernel primitive and can be
used to synchronize access to any object that might not be thread safe
on its own. Synchronization is done with a simple mutex, so access to a
MutexProtected object is potentially blocking.
Mutex now has an internal nesting variable which is there to harden it
against lock-unlock ordering issues (e.g. double unlocking).
ConditionVariable is a thin wrapper over the pthread_cond_* APIs, just
as Mutex is a wrapper over pthread_mutex.
Because ConditionVariable might want to wait on a high-level Mutex, it
needs to be friends with it.
