Warnings on podspec validation

[QuintinWillison]

We can't push the spec up to CocoaPods trunk without using --allow-warnings at the moment...

KSCrash % pod trunk push KSCrashAblyFork.podspec 
Updating spec repo `trunk`

Validating podspec
 -> KSCrashAblyFork (1.15.20-ably-6)
    - NOTE  | [KSCrashAblyFork/Recording, KSCrashAblyFork/Recording/Tools, KSCrashAblyFork/Reporting, and more...] xcodebuild:  note: Using new build system
    - NOTE  | [KSCrashAblyFork/Recording, KSCrashAblyFork/Recording/Tools, KSCrashAblyFork/Reporting, and more...] xcodebuild:  note: Planning build
    - NOTE  | [KSCrashAblyFork/Recording, KSCrashAblyFork/Recording/Tools, KSCrashAblyFork/Reporting, and more...] xcodebuild:  note: Constructing build description
    - WARN  | [KSCrashAblyFork/Recording, KSCrashAblyFork/Reporting, KSCrashAblyFork/Reporting/Filters, and more...] xcodebuild:  KSCrashAblyFork/Source/KSCrash/Recording/KSCrashReportFixer.c:196:43: warning: implicit conversion loses integer precision: 'const int64_t' (aka 'const long long') to 'time_t' (aka 'long') [-Wshorten-64-to-32]
    - NOTE  | [KSCrashAblyFork/Recording, KSCrashAblyFork/Reporting, KSCrashAblyFork/Reporting/Filters, and more...] xcodebuild:  note: Execution policy exception registration failed and was skipped: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted" (in target 'KSCrashAblyFork' from project 'Pods')
    - NOTE  | [KSCrashAblyFork/Recording, KSCrashAblyFork/Recording/Tools, KSCrashAblyFork/Reporting, and more...] xcodebuild:  note: Execution policy exception registration failed and was skipped: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted" (in target 'Pods-App' from project 'Pods')
    - NOTE  | [KSCrashAblyFork/Recording, KSCrashAblyFork/Recording/Tools, KSCrashAblyFork/Reporting, and more...] xcodebuild:  note: Execution policy exception registration failed and was skipped: Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted" (in target 'App' from project 'App')
    - NOTE  | [KSCrashAblyFork/Recording, KSCrashAblyFork/Recording/Tools, KSCrashAblyFork/Reporting, and more...] xcodebuild:  warning: Skipping code signing because the target does not have an Info.plist file and one is not being generated automatically. (in target 'App' from project 'App')
    - WARN  | [KSCrashAblyFork/Recording, KSCrashAblyFork/Reporting, KSCrashAblyFork/Reporting/Filters, and more...] xcodebuild:  KSCrashAblyFork/Source/KSCrash/Recording/Tools/KSMachineContext.c:50:27: warning: unused variable 'g_suspendedThreads' [-Wunused-variable]
    - WARN  | [KSCrashAblyFork/Recording, KSCrashAblyFork/Reporting, KSCrashAblyFork/Reporting/Filters, and more...] xcodebuild:  KSCrashAblyFork/Source/KSCrash/Recording/Tools/KSMachineContext.c:51:31: warning: unused variable 'g_suspendedThreadsCount' [-Wunused-variable]

[!] The spec did not pass validation, due to 3 warnings (but you can use `--allow-warnings` to ignore them).

At the same time it would be good to see if we can also get rid of those NOTE items. They might be simple to fix.