[130067] Compiler reports "access warnings" for classes from jars in a plugin

Xerces needed explicitly on "requires" list.

releng.wtpbuilder/build.properties

@@ -131,7 +131,7 @@ archivesFormat=*,*,*-antZip
 # being used (JDT Compiler, in our case).
 # 'showversion' causes the version of JDT Compiler to be 
 # printed to the compiler log file. 
-compilerArg=-showversion -warn:-discouraged,serial,unusedImport,forbidden
+compilerArg=-showversion -warn:-discouraged,serial,unusedImport
 
 
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