stb_c_lexer: Move token enum defn to header portion

Required some tinkering, hope I didn't mess the logic up.

This now requires the config section to be set for the header
file, and different sites that include it should agree on what
the values are. This is kind of iffy but hard to avoid.

Fixes issue #647.

stb_c_lexer.h

@@ -42,13 +42,19 @@
 //
 //   See end of file for license information.
 
-#ifdef STB_C_LEXER_IMPLEMENTATION
 #ifndef STB_C_LEXER_DEFINITIONS
 // to change the default parsing rules, copy the following lines
 // into your C/C++ file *before* including this, and then replace
-// the Y's with N's for the ones you don't want.
+// the Y's with N's for the ones you don't want. This needs to be
+// set to the same values for every place in your program where
+// stb_c_lexer.h is included.
 // --BEGIN--
 
+#if defined(Y) || defined(N)
+#error "Can only use stb_c_lexer in contexts where the preprocessor symbols 'Y' and 'N' are not defined"
+#endif
+
+
 #define STB_C_LEX_C_DECIMAL_INTS    Y   //  "0|[1-9][0-9]*"                        CLEX_intlit
 #define STB_C_LEX_C_HEX_INTS        Y   //  "0x[0-9a-fA-F]+"                       CLEX_intlit
 #define STB_C_LEX_C_OCTAL_INTS      Y   //  "[0-7]+"                               CLEX_intlit
@@ -97,7 +103,6 @@
 #define STB_C_LEXER_DEFINITIONS         // This line prevents the header file from replacing your definitions
 // --END--
 
-#endif
 #endif
 
 #ifndef INCLUDE_STB_C_LEXER_H
@@ -167,35 +172,11 @@ extern void stb_c_lexer_get_location(const stb_lexer *lexer, const char *where,
 }
 #endif
 
-#endif // INCLUDE_STB_C_LEXER_H
-
-#ifdef STB_C_LEXER_IMPLEMENTATION
-
-   #if defined(Y) || defined(N)
-   #error "Can only use stb_c_lexer in contexts where the preprocessor symbols 'Y' and 'N' are not defined"
-   #endif
-
-
 // Hacky definitions so we can easily #if on them
 #define Y(x) 1
 #define N(x) 0
 
-#if STB_C_LEX_INTEGERS_AS_DOUBLES(x)
-typedef double     stb__clex_int;
-#define intfield   real_number
-#define STB__clex_int_as_double
-#else
-typedef long       stb__clex_int;
-#define intfield   int_number
-#endif
-
-// Convert these config options to simple conditional #defines so we can more
-// easily test them once we've change the meaning of Y/N
-
-#if STB_C_LEX_PARSE_SUFFIXES(x)
-#define STB__clex_parse_suffixes
-#endif
-
+// Config variable that influence which lexer tokens get declared need to go here
 #if STB_C_LEX_C_DECIMAL_INTS(x) || STB_C_LEX_C_HEX_INTS(x) || STB_C_LEX_DEFINE_ALL_TOKEN_NAMES(x)
 #define STB__clex_define_int
 #endif
@@ -204,35 +185,6 @@ typedef long       stb__clex_int;
 #define STB__clex_define_shifts
 #endif
 
-#if STB_C_LEX_C99_HEX_FLOATS(x)
-#define STB__clex_hex_floats
-#endif
-
-#if STB_C_LEX_C_HEX_INTS(x)
-#define STB__clex_hex_ints
-#endif
-
-#if STB_C_LEX_C_DECIMAL_INTS(x)
-#define STB__clex_decimal_ints
-#endif
-
-#if STB_C_LEX_C_OCTAL_INTS(x)
-#define STB__clex_octal_ints
-#endif
-
-#if STB_C_LEX_C_DECIMAL_FLOATS(x)
-#define STB__clex_decimal_floats
-#endif
-
-#if STB_C_LEX_DISCARD_PREPROCESSOR(x)
-#define STB__clex_discard_preprocessor
-#endif
-
-#if STB_C_LEX_USE_STDLIB(x) && (!defined(STB__clex_hex_floats) || __STDC_VERSION__ >= 199901L)
-#define STB__CLEX_use_stdlib
-#include <stdlib.h>
-#endif
-
 // Now pick a definition of Y/N that's conducive to
 // defining the enum of token names.
 #if STB_C_LEX_DEFINE_ALL_TOKEN_NAMES(x) || defined(STB_C_LEXER_SELF_TEST)
@@ -287,12 +239,68 @@ enum
 
    CLEX_first_unused_token
 
-#undef Y
-#define Y(a) a
 };
 
+#undef Y
+#undef N
+
+#endif // INCLUDE_STB_C_LEXER_H
+
+#ifdef STB_C_LEXER_IMPLEMENTATION
+
+// Hacky definitions so we can easily #if on them
+#define Y(x) 1
+#define N(x) 0
+
+#if STB_C_LEX_INTEGERS_AS_DOUBLES(x)
+typedef double     stb__clex_int;
+#define intfield   real_number
+#define STB__clex_int_as_double
+#else
+typedef long       stb__clex_int;
+#define intfield   int_number
+#endif
+
+// Convert these config options to simple conditional #defines so we can more
+// easily test them once we've change the meaning of Y/N
+
+#if STB_C_LEX_PARSE_SUFFIXES(x)
+#define STB__clex_parse_suffixes
+#endif
+
+#if STB_C_LEX_C99_HEX_FLOATS(x)
+#define STB__clex_hex_floats
+#endif
+
+#if STB_C_LEX_C_HEX_INTS(x)
+#define STB__clex_hex_ints
+#endif
+
+#if STB_C_LEX_C_DECIMAL_INTS(x)
+#define STB__clex_decimal_ints
+#endif
+
+#if STB_C_LEX_C_OCTAL_INTS(x)
+#define STB__clex_octal_ints
+#endif
+
+#if STB_C_LEX_C_DECIMAL_FLOATS(x)
+#define STB__clex_decimal_floats
+#endif
+
+#if STB_C_LEX_DISCARD_PREPROCESSOR(x)
+#define STB__clex_discard_preprocessor
+#endif
+
+#if STB_C_LEX_USE_STDLIB(x) && (!defined(STB__clex_hex_floats) || __STDC_VERSION__ >= 199901L)
+#define STB__CLEX_use_stdlib
+#include <stdlib.h>
+#endif
+
 // Now for the rest of the file we'll use the basic definition where
 // where Y expands to its contents and N expands to nothing
+#undef  Y
+#define Y(a) a
 #undef N
 #define N(a)