I seem to be experiencing this same issue today, on Mac, with the develop version I downloaded today.
Previously, I was using the release of 6.1.2. I decide to try the develop. Many errors related to this.
I am using Mojave, Xcode 10.3. Just testing a simple default Audio App:
In file included from /Users/stephen/Documents/JUCE/TestAudioApplication/JuceLibraryCode/include_juce_audio_formats.mm:9:
In file included from /Users/stephen/Development/JUCE-dev clean/modules/juce_audio_formats/juce_audio_formats.mm:26:
In file included from /Users/stephen/Development/JUCE-dev clean/modules/juce_audio_formats/juce_audio_formats.cpp:67:
/Users/stephen/Development/JUCE-dev clean/modules/juce_audio_formats/codecs/juce_OggVorbisAudioFormat.cpp:53:2: error: expected unqualified-id
JUCE_BEGIN_NO_SANITIZE ("undefined")
^
In file included from /Users/stephen/Documents/JUCE/TestAudioApplication/JuceLibraryCode/include_juce_audio_formats.mm:9:
In file included from /Users/stephen/Development/JUCE-dev clean/modules/juce_audio_formats/juce_audio_formats.mm:26:
In file included from /Users/stephen/Development/JUCE-dev clean/modules/juce_audio_formats/juce_audio_formats.cpp:39:
In file included from /Users/stephen/Development/JUCE-dev clean/modules/juce_audio_formats/juce_audio_formats.h:57:
In file included from /Users/stephen/Development/JUCE-dev clean/modules/juce_audio_basics/juce_audio_basics.h:54:
In file included from /Users/stephen/Development/JUCE-dev clean/modules/juce_core/juce_core.h:204:
In file included from /Users/stephen/Development/JUCE-dev clean/modules/juce_core/system/juce_StandardHeader.h:70:
/Users/stephen/Development/JUCE-dev clean/modules/juce_core/system/juce_CompilerWarnings.h:214:9: note: expanded from macro 'JUCE_BEGIN_NO_SANITIZE'
_Pragma(JUCE_TO_STRING(clang attribute push(__attribute__((no_sanitize(warnings))), apply_to=function)))
^