Move concat_strings from path.c

src/path.c

@@ -283,18 +283,6 @@ char_u *concat_fnames(char_u *fname1, char_u *fname2, int sep)
   return dest;
 }
 
-/*
- * Concatenate two strings and return the result in allocated memory.
- */
-char_u *concat_str(char_u *str1, char_u *str2)
-{
-  size_t l = STRLEN(str1);
-  char_u *dest = xmalloc(l + STRLEN(str2) + 1);
-  STRCPY(dest, str1);
-  STRCPY(dest + l, str2);
-  return dest;
-}
-
 /*
  * Add a path separator to a file name, unless it already ends in a path
  * separator.

src/strings.c

@@ -534,3 +534,17 @@ int has_non_ascii(char_u *s)
   return FALSE;
 }
 #endif
+
+/*
+ * Concatenate two strings and return the result in allocated memory.
+ * Returns NULL when out of memory.
+ */
+char_u *concat_str(char_u *str1, char_u *str2)
+{
+  size_t l = STRLEN(str1);
+  char_u *dest = xmalloc(l + STRLEN(str2) + 1);
+  STRCPY(dest, str1);
+  STRCPY(dest + l, str2);
+  return dest;
+}
+

src/strings.h

@@ -23,4 +23,5 @@ char_u *vim_strbyte(char_u *string, int c);
 char_u *vim_strrchr(char_u *string, int c);
 int vim_isspace(int x);
 void sort_strings(char_u **files, int count);
+char_u *concat_str(char_u *str1, char_u *str2);
 #endif