diff --git a/src/libavrdude.h b/src/libavrdude.h
index 728a3452..eff89785 100644
--- a/src/libavrdude.h
+++ b/src/libavrdude.h
@@ -1486,6 +1486,7 @@ const char *str_ccprintf(const char *fmt, ...)
 ;
 const char *str_ccstrdup(const char *str);
 char *str_fgets(FILE *fp, const char **errpp);
+size_t str_numc(const char *str, char c);
 char *str_lc(char *s);
 char *str_uc(char *s);
 char *str_lcfirst(char *s);
diff --git a/src/strutil.c b/src/strutil.c
index 7a8e0085..8c7e42cf 100644
--- a/src/strutil.c
+++ b/src/strutil.c
@@ -77,7 +77,6 @@ int str_caseends(const char *str, const char *ends) {
   return str_caseeq(str + str_len - ends_len, ends);
 }
 
-
 /*
  * Match string against the partname pattern, returning 1 if it matches, 0 if
  * not. Note: str_match_core() is a modified old copy of !fnmatch() from the
@@ -337,6 +336,17 @@ char *str_fgets(FILE *fp, const char **errpp) {
 }
 
 
+// Return the number of times a character c occurs in str
+size_t str_numc(const char *str, char c) {
+  size_t ret = 0;
+  char is;
+
+  while((is = *str++))
+    if(is == c)
+      ret++;
+  return ret;
+}
+
 // Changes string to be all lowercase and returns original pointer
 char *str_lc(char *s) {
   for(char *t = s; *t; t++)