[C++] Always output a #line as first line of the pp output.

Change-Id: I60d25109ae8fe3628b1899078a21010263787c33
Reviewed-by: Roberto Raggi <roberto.raggi@nokia.com>

tests/auto/cplusplus/preprocessor/data/empty-macro.2.out.cpp

@@ -1,3 +1,4 @@
+# 1 "data/empty-macro.2.cpp"
 # 6 "data/empty-macro.2.cpp"
 class Test {
 private:

tests/auto/cplusplus/preprocessor/data/empty-macro.out.cpp

@@ -1,3 +1,4 @@
+# 1 "data/empty-macro.cpp"
 
 
 class             Foo {

tests/auto/cplusplus/preprocessor/data/identifier-expansion.1.out.cpp

@@ -1,3 +1,4 @@
+# 1 "data/identifier-expansion.1.cpp"
 #gen true
 # 1 "data/identifier-expansion.1.cpp"
 test test

tests/auto/cplusplus/preprocessor/data/identifier-expansion.2.out.cpp

@@ -1,3 +1,4 @@
+# 1 "data/identifier-expansion.2.cpp"
 #gen true
 # 1 "data/identifier-expansion.2.cpp"
 test test

tests/auto/cplusplus/preprocessor/data/identifier-expansion.3.out.cpp

@@ -1,3 +1,4 @@
+# 1 "data/identifier-expansion.3.cpp"
 # 8 "data/identifier-expansion.3.cpp"
 enum op_code {
 #gen true

tests/auto/cplusplus/preprocessor/data/identifier-expansion.4.out.cpp

@@ -1,3 +1,4 @@
+# 1 "data/identifier-expansion.4.cpp"
 
 
 

tests/auto/cplusplus/preprocessor/data/identifier-expansion.5.out.cpp

@@ -1 +1,2 @@
+# 1 "data/identifier-expansion.5.cpp"
 # 9 "data/identifier-expansion.5.cpp"

tests/auto/cplusplus/preprocessor/data/macro-test.out.cpp

@@ -1,3 +1,4 @@
+# 1 "data/macro-test.cpp"
 # 7 "data/macro-test.cpp"
 void thisFunctionIsEnabled();
 # 21 "data/macro-test.cpp"

tests/auto/cplusplus/preprocessor/data/macro_expand.out.c

@@ -1,3 +1,4 @@
+# 1 "data/macro_expand.c"
 
 
 

tests/auto/cplusplus/preprocessor/data/recursive.1.out.cpp

@@ -1,3 +1,4 @@
+# 1 "data/recursive.1.cpp"
 #gen true
 # 1 "data/recursive.1.cpp"
 b

tests/auto/cplusplus/preprocessor/data/reserved.1.out.cpp

@@ -1,3 +1,4 @@
+# 1 "data/reserved.1.cpp"
 # 5 "data/reserved.1.cpp"
 int f() {
     foreach (QString &s, QStringList()) {