tools lib: Adopt strreplace() from the kernel

We'll use it to further reduce the size of tools/perf/util/string.c,
replacing the strxfrchar() equivalent function we have there.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-x3r61ikjrso1buygxwke8id3@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/include/linux/string.h

@@ -19,6 +19,8 @@ extern size_t strlcpy(char *dest, const char *src, size_t size);
 
 char *str_error_r(int errnum, char *buf, size_t buflen);
 
+char *strreplace(char *s, char old, char new);
+
 /**
  * strstarts - does @str start with @prefix?
  * @str: string to examine

tools/lib/string.c

@@ -145,3 +145,19 @@ char *strim(char *s)
 
 	return skip_spaces(s);
 }
+
+/**
+ * strreplace - Replace all occurrences of character in string.
+ * @s: The string to operate on.
+ * @old: The character being replaced.
+ * @new: The character @old is replaced with.
+ *
+ * Returns pointer to the nul byte at the end of @s.
+ */
+char *strreplace(char *s, char old, char new)
+{
+	for (; *s; ++s)
+		if (*s == old)
+			*s = new;
+	return s;
+}