Fix mnemonics bug introduced in commit b84c583a

We want to not expand tilde to attributes when there are any attribute codes
in the mnemonics string. The existene of a non-attribute ctrl-a code should
not have prevented the tilde expansion.

Fix for issue #805 reported by Nelgin (thank you)

src/sbbs3/getkey.cpp

@@ -182,7 +182,7 @@ void sbbs_t::mnemonics(const char *instr)
 		bputs(instr);
 		return; 
 	}
-	bool ctrl_a_codes = (strchr(instr, CTRL_A) != NULL) && !contains_invalid_attr(instr);
+	bool ctrl_a_codes = contains_ctrl_a_attr(instr);
 	if(!ctrl_a_codes) {
 		const char* last = lastchar(instr);
 		if(instr[0] == '@' && *last == '@' && strchr(instr + 1, '@') == last && strchr(instr, ' ') == NULL) {

src/sbbs3/str_util.c

@@ -535,16 +535,15 @@ size_t strip_invalid_attr(char *str)
 }
 
 /****************************************************************************/
-/* Detects invalid Ctrl-Ax "attribute" sequences in str                    	*/
-/* Returns number of ^A's in line                                           */
+/* Detects valid Ctrl-Ax "attribute" sequences in str                    	*/
 /****************************************************************************/
-bool contains_invalid_attr(const char *str)
+bool contains_ctrl_a_attr(const char *str)
 {
 
 	while(*str != '\0') {
 		if(*str == CTRL_A) {
 			++str;
-			if(!valid_ctrl_a_attr(*str))
+			if(valid_ctrl_a_attr(*str))
 				return true;
 		}
 		++str;

src/sbbs3/str_util.h

@@ -57,7 +57,7 @@ DLLEXPORT char *	strip_char(const char* str, char* dest, char);
 DLLEXPORT bool		valid_ctrl_a_attr(char a);
 DLLEXPORT bool		valid_ctrl_a_code(char a);
 DLLEXPORT size_t	strip_invalid_attr(char *str);
-DLLEXPORT bool		contains_invalid_attr(const char*);
+DLLEXPORT bool		contains_ctrl_a_attr(const char*);
 DLLEXPORT char *	u32toac(uint32_t, char*, char sep);
 DLLEXPORT char *	u64toac(uint64_t, char*, char sep);
 DLLEXPORT char *	rot13(char* str);