#1297 Do not parse headers when searchi!ng for headers

Caused a nearly lock up on my system with the library exclusion filters
not set

Author: jantje

io.sloeber.core/src/io/sloeber/core/tools/PdePreprocessor.java

@@ -210,7 +210,7 @@ private static String extendHeaderForFile(String header, IIndex index, ITranslat
 		String localHeader = header;
 		// Locate All lines that are extern "C"
 		HashMap<Integer, Integer> externCLines = new HashMap<>();
-		IASTTranslationUnit astTuTest = tu.getAST(index, 0);
+        IASTTranslationUnit astTuTest = tu.getAST(index, ITranslationUnit.AST_SKIP_ALL_HEADERS);
 		IASTDeclaration[] topDeclaratons = astTuTest.getDeclarations();
 		for (IASTDeclaration curTopDeclaration : topDeclaratons) {