$ grep 'does not exist' /var/tmp/portage/dev-java/netty-common-4.1.56/temp/build.log
src/main/java/io/netty/util/internal/svm/UnsafeRefArrayAccessSubstitution.java:18: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/UnsafeRefArrayAccessSubstitution.java:19: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/UnsafeRefArrayAccessSubstitution.java:20: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/PlatformDependentSubstitution.java:18: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/PlatformDependentSubstitution.java:19: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/PlatformDependentSubstitution.java:20: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/PlatformDependent0Substitution.java:18: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/PlatformDependent0Substitution.java:19: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/PlatformDependent0Substitution.java:20: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/CleanerJava6Substitution.java:18: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/CleanerJava6Substitution.java:19: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/svm/CleanerJava6Substitution.java:20: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/internal/Hidden.java:20: error: package reactor.blockhound does not exist
src/main/java/io/netty/util/internal/Hidden.java:21: error: package reactor.blockhound.integration does not exist
src/main/java/io/netty/util/internal/Hidden.java:42: error: package BlockHound does not exist
src/main/java/io/netty/util/NetUtilSubstitutions.java:18: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/NetUtilSubstitutions.java:19: error: package com.oracle.svm.core.annotate does not exist
src/main/java/io/netty/util/NetUtilSubstitutions.java:20: error: package com.oracle.svm.core.annotate does not exist