Distinguish anonymous declarations

New type constructor `QualNameAnon` is added to the `QualName` type to
distinguish anonymous declarations in binding specifications and select
predicates.  The string representation uses an `@` prefix.

Example: `@SC_c`

This character should not cause issues with regular expressions.

This character is reserved for future use by YAML and must therefore be
quoted.

Example:

```yaml
cname: '@S1_c'
```

Author: TravisCardwell

hs-bindgen/fixtures/anonymous.bindingspec.yaml

@@ -8,47 +8,47 @@ types:
   - Show
   - Storable
 - headers: anonymous.h
-  cname: S1_c
+  cname: struct S2
   module: Example
-  identifier: S1_c
+  identifier: S2
   instances:
   - Eq
   - Show
   - Storable
 - headers: anonymous.h
-  cname: struct S2
+  cname: struct S3
   module: Example
-  identifier: S2
+  identifier: S3
   instances:
   - Eq
   - Show
   - Storable
 - headers: anonymous.h
-  cname: S2_inner
+  cname: '@S1_c'
   module: Example
-  identifier: S2_inner
+  identifier: S1_c
   instances:
   - Eq
   - Show
   - Storable
 - headers: anonymous.h
-  cname: S2_inner_deep
+  cname: '@S2_inner'
   module: Example
-  identifier: S2_inner_deep
+  identifier: S2_inner
   instances:
   - Eq
   - Show
   - Storable
 - headers: anonymous.h
-  cname: struct S3
+  cname: '@S2_inner_deep'
   module: Example
-  identifier: S3
+  identifier: S2_inner_deep
   instances:
   - Eq
   - Show
   - Storable
 - headers: anonymous.h
-  cname: S3_c
+  cname: '@S3_c'
   module: Example
   identifier: S3_c
   instances:

hs-bindgen/fixtures/attributes.bindingspec.yaml

@@ -16,23 +16,23 @@ types:
   - Show
   - Storable
 - headers: attributes.h
-  cname: baz
+  cname: struct foo
   module: Example
-  identifier: Baz
+  identifier: Foo
   instances:
   - Eq
   - Show
   - Storable
 - headers: attributes.h
-  cname: struct foo
+  cname: '@baz'
   module: Example
-  identifier: Foo
+  identifier: Baz
   instances:
   - Eq
   - Show
   - Storable
 - headers: attributes.h
-  cname: qux
+  cname: '@qux'
   module: Example
   identifier: Qux
   instances:

hs-bindgen/fixtures/distilled_lib_1.bindingspec.yaml

@@ -18,65 +18,65 @@ types:
   - Real
   - Storable
 - headers: distilled_lib_1.h
-  cname: a_typedef_enum_e
+  cname: struct a_typedef_struct
   module: Example
-  identifier: A_typedef_enum_e
+  identifier: A_typedef_struct_t
   instances:
   - Eq
-  - Ord
-  - Read
   - Show
   - Storable
 - headers: distilled_lib_1.h
-  cname: struct a_typedef_struct
+  cname: callback_t
   module: Example
-  identifier: A_typedef_struct_t
+  identifier: Callback_t
   instances:
   - Eq
+  - Ord
   - Show
   - Storable
 - headers: distilled_lib_1.h
-  cname: another_typedef_enum_e
+  cname: var_t
   module: Example
-  identifier: Another_typedef_enum_e
+  identifier: Var_t
   instances:
   - Eq
   - Ord
+  - Enum
+  - Ix
+  - Bounded
   - Read
   - Show
+  - Bits
+  - FiniteBits
+  - Integral
+  - Num
+  - Real
   - Storable
 - headers: distilled_lib_1.h
-  cname: another_typedef_struct_t
+  cname: '@a_typedef_enum_e'
   module: Example
-  identifier: Another_typedef_struct_t
+  identifier: A_typedef_enum_e
   instances:
   - Eq
+  - Ord
+  - Read
   - Show
   - Storable
 - headers: distilled_lib_1.h
-  cname: callback_t
+  cname: '@another_typedef_enum_e'
   module: Example
-  identifier: Callback_t
+  identifier: Another_typedef_enum_e
   instances:
   - Eq
   - Ord
+  - Read
   - Show
   - Storable
 - headers: distilled_lib_1.h
-  cname: var_t
+  cname: '@another_typedef_struct_t'
   module: Example
-  identifier: Var_t
+  identifier: Another_typedef_struct_t
   instances:
   - Eq
-  - Ord
-  - Enum
-  - Ix
-  - Bounded
-  - Read
   - Show
-  - Bits
-  - FiniteBits
-  - Integral
-  - Num
-  - Real
   - Storable

hs-bindgen/fixtures/enum_cpp_syntax.bindingspec.yaml

@@ -1,6 +1,6 @@
 types:
 - headers: enum_cpp_syntax.h
-  cname: foo_enum
+  cname: '@foo_enum'
   module: Example
   identifier: Foo_enum
   instances:

hs-bindgen/fixtures/enums.bindingspec.yaml

@@ -1,14 +1,4 @@
 types:
-- headers: enums.h
-  cname: enumA
-  module: Example
-  identifier: EnumA
-  instances:
-  - Eq
-  - Ord
-  - Read
-  - Show
-  - Storable
 - headers: enums.h
   cname: enum enumB
   module: Example
@@ -89,3 +79,13 @@ types:
   - Read
   - Show
   - Storable
+- headers: enums.h
+  cname: '@enumA'
+  module: Example
+  identifier: EnumA
+  instances:
+  - Eq
+  - Ord
+  - Read
+  - Show
+  - Storable

hs-bindgen/fixtures/flam.bindingspec.yaml

@@ -16,17 +16,17 @@ types:
   - Show
   - Storable
 - headers: flam.h
-  cname: foo_bar
+  cname: struct pascal
   module: Example
-  identifier: Foo_bar
+  identifier: Pascal
   instances:
   - Eq
   - Show
   - Storable
 - headers: flam.h
-  cname: struct pascal
+  cname: '@foo_bar'
   module: Example
-  identifier: Pascal
+  identifier: Foo_bar
   instances:
   - Eq
   - Show

hs-bindgen/fixtures/fun_attributes.bindingspec.yaml

@@ -1,12 +1,4 @@
 types:
-- headers: fun_attributes.h
-  cname: FILE
-  module: Example
-  identifier: FILE
-  instances:
-  - Eq
-  - Show
-  - Storable
 - headers: fun_attributes.h
   cname: size_t
   module: Example
@@ -25,3 +17,11 @@ types:
   - Num
   - Real
   - Storable
+- headers: fun_attributes.h
+  cname: '@FILE'
+  module: Example
+  identifier: FILE
+  instances:
+  - Eq
+  - Show
+  - Storable

hs-bindgen/fixtures/globals.bindingspec.yaml

@@ -16,23 +16,23 @@ types:
   - Show
   - Storable
 - headers: globals.h
-  cname: struct1_t
+  cname: '@struct1_t'
   module: Example
   identifier: Struct1_t
   instances:
   - Eq
   - Show
   - Storable
 - headers: globals.h
-  cname: struct2_t
+  cname: '@struct2_t'
   module: Example
   identifier: Struct2_t
   instances:
   - Eq
   - Show
   - Storable
 - headers: globals.h
-  cname: version_t
+  cname: '@version_t'
   module: Example
   identifier: Version_t
   instances:

hs-bindgen/fixtures/macro_in_fundecl_vs_typedef.bindingspec.yaml

@@ -43,14 +43,6 @@ types:
   - Eq
   - Show
   - Storable
-- headers: macro_in_fundecl_vs_typedef.h
-  cname: struct2
-  module: Example
-  identifier: Struct2
-  instances:
-  - Eq
-  - Show
-  - Storable
 - headers: macro_in_fundecl_vs_typedef.h
   cname: struct struct3
   module: Example
@@ -75,3 +67,11 @@ types:
   - Eq
   - Show
   - Storable
+- headers: macro_in_fundecl_vs_typedef.h
+  cname: '@struct2'
+  module: Example
+  identifier: Struct2
+  instances:
+  - Eq
+  - Show
+  - Storable

hs-bindgen/fixtures/macro_typedef_struct.bindingspec.yaml

@@ -18,7 +18,7 @@ types:
   - Real
   - Storable
 - headers: macro_typedef_struct.h
-  cname: bar
+  cname: '@bar'
   module: Example
   identifier: Bar
   instances: