Add -Wno-availability to WARNING_FLAGS when building with clang static analyzer

[David Kilzer (:ddkilzer)]

Add -Wno-availability to WARNING_FLAGS when building with clang static analyzer.

The clang static analyzer from open source clang-17 doesn't know about the iosmac platform, so we get a stream of warnings-as-errors with -Wavailability checks.

Example:

WebKitBuild/Release/usr/local/include/pal/spi/cocoa/AVFoundationSPI.h:440:94: error: unknown platform 'iosmac' in availability macro [-Werror,-Wavailability]
  440 | - (instancetype)initWithAssumedIdentity:(tcc_identity_t)tccIdentity SPI_AVAILABLE(ios(15.0)) API_UNAVAILABLE(macos, macCatalyst, watchos, tvos);
      |                                                                                              ^
In file included from Source/WebCore/PAL/pal/avfoundation/OutputDevice.mm:26:
In file included from Source/WebCore/PAL/config.h:36:
In file included from WebKitBuild/Release/usr/local/include/wtf/FastMalloc.h:26:
In file included from WebKitBuild/Release/usr/local/include/wtf/StdLibExtras.h:34:
In file included from WebKitBuild/Release/usr/local/include/wtf/Assertions.h:55:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.Internal.sdk/usr/include/os/log.h:11:
/Applications/Xcode2.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.Internal.sdk/usr/include/os/availability.h:154:169: note: expanded from macro 'API_UNAVAILABLE'
  154 |     #define API_UNAVAILABLE(...) __API_UNAVAILABLE_GET_MACRO(__VA_ARGS__,__API_UNAVAILABLE8,__API_UNAVAILABLE7,__API_UNAVAILABLE6,__API_UNAVAILABLE5,__API_UNAVAILABLE4,__API_UNAVAILABLE3,__API_UNAVAILABLE2,__API_UNAVAILABLE1,__API_UNAVAILABLE0,0)(__VA_ARGS__)
      |                                                                                                                                                                         ^
1 error generated.

[Radar WebKit Bug Importer]

<rdar://problem/120711320>

[David Kilzer (:ddkilzer)]

Pull request: https://github.com/WebKit/WebKit/pull/22550

[Elliott Williams]

> WebKitBuild/Release/usr/local/include/pal/spi/cocoa/AVFoundationSPI.h:440:94: error: unknown platform 'iosmac' in availability macro [-Werror,-Wavailability]
>   440 | - (instancetype)initWithAssumedIdentity:(tcc_identity_t)tccIdentity SPI_AVAILABLE(ios(15.0)) API_UNAVAILABLE(macos, macCatalyst, watchos, tvos);
>       |                                                                                              ^

It's weird that this is complaining about "iosmac" when the declaration says "macCatalyst".

Upstream clang does appear to know about "maccatalyst": https://github.com/llvm/llvm-project/blob/a1dc813f759955ddbcf9b12ed052dfc8a07fdf4a/clang/include/clang/Basic/Attr.td#L974C29-L974C29

[Elliott Williams]

Ah, usr/include/AvailabilityInternal.h is rewrites "macCatalyst" to "iosmac" in the internal SDK only. I've filed rdar://120799823 with more information.

[Elliott Williams]

(Re-posting <rdar://problem/120711320> to make the bug importer happy.)

[David Kilzer (:ddkilzer)]

Not going to land this fix.  See the PR for details (this is not a supported configuration):

<https://github.com/WebKit/WebKit/pull/22550#issuecomment-1886077808>