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

Sun Studio on Solaris issues warnings about improper initialization
values being used when defining tolower_trans_tbl[] in ctype.c.  The
array wants to store values with high-bit set and treat them as
values between 128 to 255.  Unlike the rest of the Git codebase
where we explicitly specify 'unsigned char' for such variables and
arrays, however, kwset code we borrowed from elsewhere uses 'char'
for this and other variables.

Fix the declarations to explicitly use 'unsigned char' where
necessary to bring it in line with the rest of the Git.

Signed-off-by: Ben Walton <bdwalton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

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

@@ -554,7 +554,7 @@ static inline int has_extension(const char *filename, const char *ext)
 }
 
 /* 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