Add utf8_to_uv_error(s)

This is just utf8n_to_uvchr_error() with a more convenient API that is
harder to misuse.

New code should use this new function instead of the old.

Author: khwilliamson

embed.fnc

@@ -3733,6 +3733,13 @@ AMdip	|UV	|utf8_to_uvchr_buf					\
 				|NN const U8 *s 			\
 				|NN const U8 *send			\
 				|NULLOK STRLEN *retlen
+ATmp	|bool	|utf8_to_uv_errors					\
+				|NN const U8 * const s			\
+				|NN const U8 * const e			\
+				|NN UV *cp_p				\
+				|NULLOK Size_t *advance_p		\
+				|const U32 flags			\
+				|NULLOK U32 *errors
 ATip	|bool	|utf8_to_uv_msgs|NN const U8 * const s0 		\
 				|NN const U8 *e 			\
 				|NN UV *cp_p				\

embed.h

@@ -862,6 +862,7 @@
 # define utf8_to_bytes_new_pv(a,b,c)            Perl_utf8_to_bytes_new_pv(aTHX,a,b,c)
 # define utf8_to_bytes_overwrite(a,b)           Perl_utf8_to_bytes_overwrite(aTHX,a,b)
 # define utf8_to_bytes_temp_pv(a,b)             Perl_utf8_to_bytes_temp_pv(aTHX,a,b)
+# define utf8_to_uv_errors                      Perl_utf8_to_uv_errors
 # define utf8_to_uv_msgs                        Perl_utf8_to_uv_msgs
 # define utf8_to_uv_msgs_helper_                Perl_utf8_to_uv_msgs_helper_
 # define utf8n_to_uvchr                         Perl_utf8n_to_uvchr

proto.h

@@ -159,6 +159,9 @@ typedef enum {
 #define Perl_utf8n_to_uvchr_error(s, len, lenp, flags, errors)                 \
                     Perl_utf8n_to_uvchr_msgs(s, len, lenp, flags, errors, 0)
 
+#define Perl_utf8_to_uv_errors(  s, e, cp_p, advance_p, flags, errors)      \
+          Perl_utf8_to_uv_msgs(  s, e, cp_p, advance_p, flags, errors, 0)
+
 #define utf16_to_utf8(p, d, bytelen, newlen)                                \
                             utf16_to_utf8_base(p, d, bytelen, newlen, 0, 1)
 #define utf16_to_utf8_reversed(p, d, bytelen, newlen)                       \