Don't compare foreign values to enumeration type

Clang warns when comparing an enumeration type with a value not found
in this enumeration:

warning: comparison of constant VALUE with expression of type 'TYPE' is
      always false [-Wtautological-constant-out-of-range-compare]

If the compiler then decides to optimize the test away because it
assumes the it is indeed always false, it can lead to pretty subtle and
nasty issues.

Ported universal-ctags patch from Colomban Wendling

ctags/parsers/c.c

@@ -57,7 +57,7 @@ typedef enum eException
 
 /*  Used to specify type of keyword.
  */
-typedef enum eKeywordId
+enum eKeywordId
 {
 	KEYWORD_ATTRIBUTE, KEYWORD_ABSTRACT, KEYWORD_ALIAS,
 	KEYWORD_BOOLEAN, KEYWORD_BYTE, KEYWORD_BAD_STATE, KEYWORD_BAD_TRANS,
@@ -92,7 +92,8 @@ typedef enum eKeywordId
 	KEYWORD_USING,
 	KEYWORD_VIRTUAL, KEYWORD_VOID, KEYWORD_VOLATILE,
 	KEYWORD_WCHAR_T, KEYWORD_WEAK, KEYWORD_WHILE
-} keywordId;
+};
+typedef int keywordId; /* to allow KEYWORD_NONE */
 
 /*  Used to determine whether keyword is valid for the current language and
  *  what its ID is.

ctags/parsers/fortran.c

@@ -61,7 +61,7 @@ typedef enum eFortranLineType {
 
 /*  Used to specify type of keyword.
  */
-typedef enum eKeywordId {
+enum eKeywordId {
 	KEYWORD_allocatable,
 	KEYWORD_assignment,
 	KEYWORD_associate,
@@ -140,7 +140,8 @@ typedef enum eKeywordId {
 	KEYWORD_volatile,
 	KEYWORD_where,
 	KEYWORD_while
-} keywordId;
+};
+typedef int keywordId; /* to allow KEYWORD_NONE */
 
 typedef enum eTokenType {
 	TOKEN_UNDEFINED,

ctags/parsers/go.c

@@ -27,7 +27,7 @@
  *	 DATA DECLARATIONS
  */
 
-typedef enum eKeywordId {
+enum eKeywordId {
 	KEYWORD_package,
 	KEYWORD_import,
 	KEYWORD_const,
@@ -38,7 +38,8 @@ typedef enum eKeywordId {
 	KEYWORD_interface,
 	KEYWORD_map,
 	KEYWORD_chan
-} keywordId;
+};
+typedef int keywordId; /* to allow KEYWORD_NONE */
 
 typedef enum eTokenType {
 	TOKEN_NONE = -1,

ctags/parsers/jscript.c

@@ -51,7 +51,7 @@ static stringList *FunctionNames;
 
 /*	Used to specify type of keyword.
 */
-typedef enum eKeywordId {
+enum eKeywordId {
 	KEYWORD_function,
 	KEYWORD_capital_function,
 	KEYWORD_capital_object,
@@ -72,7 +72,8 @@ typedef enum eKeywordId {
 	KEYWORD_finally,
 	KEYWORD_sap,
 	KEYWORD_return
-} keywordId;
+};
+typedef int keywordId; /* to allow KEYWORD_NONE */
 
 typedef enum eTokenType {
 	TOKEN_UNDEFINED,

ctags/parsers/php.c

@@ -24,7 +24,7 @@
 #define SCOPE_SEPARATOR "::"
 
 
-typedef enum {
+enum {
 	KEYWORD_abstract,
 	KEYWORD_and,
 	KEYWORD_as,
@@ -84,7 +84,8 @@ typedef enum {
 	KEYWORD_while,
 	KEYWORD_xor,
 	KEYWORD_yield
-} keywordId;
+};
+typedef int keywordId; /* to allow KEYWORD_NONE */
 
 typedef enum {
 	ACCESS_UNDEFINED,

ctags/parsers/sql.c

@@ -53,7 +53,7 @@ typedef enum eException { ExceptionNone, ExceptionEOF } exception_t;
 /*
  * Used to specify type of keyword.
  */
-typedef enum eKeywordId {
+enum eKeywordId {
 	KEYWORD_is,
 	KEYWORD_begin,
 	KEYWORD_body,
@@ -126,7 +126,8 @@ typedef enum eKeywordId {
 	KEYWORD_comment,
 	KEYWORD_create,
 	KEYWORD_go
-} keywordId;
+};
+typedef int keywordId; /* to allow KEYWORD_NONE */
 
 typedef enum eTokenType {
 	TOKEN_UNDEFINED,