Add regression test for parsing of enums with underlying type specification

Author: danpoe

regression/ansi-c/enum9/main.c

@@ -0,0 +1,20 @@
+typedef enum : unsigned
+{
+  X
+} my_enum1;
+
+enum my_enum2 : unsigned
+{
+  Y
+};
+
+struct S
+{
+  enum my_enum2 : unsigned a;
+  enum my_enum2 : unsigned b : 2;
+};
+
+int main()
+{
+  enum my_enum2 : unsigned enum_var1;
+}

regression/ansi-c/enum9/test.desc

@@ -0,0 +1,14 @@
+CORE
+main.c
+--verbosity 2
+^EXIT=0$
+^SIGNAL=0$
+main.c:1:1: warning: ignoring specification of underlying type for enum
+main.c:6:1: warning: ignoring specification of underlying type for enum
+main.c:13:1: warning: ignoring specification of underlying type for enum
+main.c:14:1: warning: ignoring specification of underlying type for enum
+main.c:19:1: warning: ignoring specification of underlying type for enum
+--
+--
+Checks that files containing enums with an underlying type specification can be
+parsed, and that a warning is output saying that the specification is ignored