[pcre2] Disable JIT when targeting iOS

[fwcd]

PCRE2 JIT compilation is unsupported on iOS as per https://codereview.qt-project.org/c/qt/qtbase/+/204514

Since our Qt port uses the separately built pcre2 port (instead of the bundled version):

vcpkg/ports/qtbase/portfile.cmake

Line 315 in 3f966cf

-DQT_USE_BUNDLED_BundledPcre2:BOOL=FALSE

...the linked Qt fix doesn't apply to us, so we'll have to disable it explicitly.

Background

I ran into this today while debugging a crash of a Qt app built for the iOS simulator (using vcpkg-built libraries):

Crash Log

Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Subtype: KERN_PROTECTION_FAILURE at 0x000000010dbb8008
Exception Codes: 0x0000000000000002, 0x000000010dbb8008
VM Region Info: 0x10dbb8008 is in 0x10dbb8000-0x10dbc8000;  bytes after start: 8  bytes before end: 65527
      REGION TYPE                    START - END         [ VSIZE] PRT/MAX SHRMOD  REGION DETAIL
      ColorSync                   10dbb0000-10dbb8000    [   32K] r--/r-- SM=PRV  
--->  VM_ALLOCATE                 10dbb8000-10dbc8000    [   64K] rwx/rwx SM=PRV  
      GAP OF 0x38000 BYTES
      MALLOC_TINY                 10dc00000-10dd00000    [ 1024K] rw-/rwx SM=PRV  
Termination Reason: SIGNAL 10 Bus error: 10
Terminating Process: exc handler [98229]

Triggered by Thread:  0

Thread 0 Crashed::  Dispatch queue: com.apple.main-thread
0   Mixxx                         	       0x107b8ec24 sljit_malloc_exec + 236
1   Mixxx                         	       0x107b8ea80 pcre2_jit_compile_16 + 160
2   Mixxx                         	       0x104ec52d4 QRegularExpressionPrivate::compilePattern() + 252
3   Mixxx                         	       0x104ec6058 QRegularExpression::isValid() const + 24
4   Mixxx                         	       0x104e30194 QtPrivate::contains(QStringView, QString const*, QRegularExpression const&, QRegularExpressionMatch*) + 52
5   Mixxx                         	       0x10599a8ec QIOSScreen::QIOSScreen(UIScreen*) + 1060
6   Mixxx                         	       0x105998850 QIOSIntegration::initialize() + 272
7   Mixxx                         	       0x104d8165c QCoreApplicationPrivate::init() + 1640
8   Mixxx                         	       0x1076c80e0 QGuiApplicationPrivate::init() + 60
9   Mixxx                         	       0x105d9d20c QApplicationPrivate::init() + 24
10  Mixxx                         	       0x105d9d1e0 QApplication::QApplication(int&, char**, int) + 140

This fixes the problem.

Checklist

• Changes comply with the maintainer guide.
• SHA512s are updated for each updated download (not applicable).
• The "supports" clause reflects platforms that may be fixed by this new version.
• Any fixed CI baseline entries are removed from that file (not applicable).
• Any patches that are no longer applied are deleted from the port's directory (not applicable).
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Only one version is added to each modified port's versions file.

[WangWeiLin-MV]

P.S. According to the comment PCRE2Project/pcre2#212 (comment) from upstream, PCRE2 should disable JIT when the target is iOS.