Merge branch 'bw/kwset-use-unsigned' into maint

The borrowed code in kwset API did not follow our usual convention
to use "unsigned char" to store values that range from 0-255.

* bw/kwset-use-unsigned:
  kwset: use unsigned char to store values with high-bit set

ctype.c

@@ -30,7 +30,7 @@ const unsigned char sane_ctype[256] = {
 };
 
 /* For case-insensitive kwset */
-const char tolower_trans_tbl[256] = {
+const unsigned char tolower_trans_tbl[256] = {
 	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
 	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
 	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,

git-compat-util.h

@@ -688,7 +688,7 @@ static inline size_t xsize_t(off_t len)
 }
 
 /* in ctype.c, for kwset users */
-extern const char tolower_trans_tbl[256];
+extern const unsigned char tolower_trans_tbl[256];
 
 /* Sane ctype - no locale, and works with signed chars */
 #undef isascii

kwset.c

@@ -80,13 +80,13 @@ struct kwset
   struct trie *next[NCHAR];	/* Table of children of the root. */
   char *target;			/* Target string if there's only one. */
   int mind2;			/* Used in Boyer-Moore search for one string. */
-  char const *trans;		/* Character translation table. */
+  unsigned char const *trans;  /* Character translation table. */
 };
 
 /* Allocate and initialize a keyword set object, returning an opaque
    pointer to it.  Return NULL if memory is not available. */
 kwset_t
-kwsalloc (char const *trans)
+kwsalloc (unsigned char const *trans)
 {
   struct kwset *kwset;
 
@@ -381,7 +381,7 @@ kwsprep (kwset_t kws)
   register struct kwset *kwset;
   register int i;
   register struct trie *curr;
-  register char const *trans;
+  register unsigned char const *trans;
   unsigned char delta[NCHAR];
 
   kwset = (struct kwset *) kws;
@@ -590,7 +590,7 @@ cwexec (kwset_t kws, char const *text, size_t len, struct kwsmatch *kwsmatch)
   register int d;
   register char const *end, *qlim;
   register struct tree const *tree;
-  register char const *trans;
+  register unsigned char const *trans;
 
   accept = NULL;
 

kwset.h

@@ -39,7 +39,7 @@ typedef struct kwset_t* kwset_t;
    if enough memory cannot be obtained.  The argument if non-NULL
    specifies a table of character translations to be applied to all
    pattern and search text. */
-extern kwset_t kwsalloc(char const *);
+extern kwset_t kwsalloc(unsigned char const *);
 
 /* Incrementally extend the keyword set to include the given string.
    Return NULL for success, or an error message.  Remember an index