Cryptlib: implement strcmp() and strcasecmp()

strcmp() and strcasecmp() are widely used in openssl. Implement those
two functions to eliminate the gcc warnings and the potential crash.

Signed-off-by: Gary Lin <glin@suse.com>

Cryptlib/Include/OpenSslSupport.h

@@ -366,7 +366,6 @@ extern FILE  *stdout;
 #define memchr(buf,ch,count)              ScanMem8(buf,(UINTN)(count),(UINT8)ch)
 #define memcmp(buf1,buf2,count)           (int)(CompareMem(buf1,buf2,(UINTN)(count)))
 #define memmove(dest,source,count)        CopyMem(dest,source,(UINTN)(count))
-#define strcmp                            strcmpa
 #define strncmp(string1,string2,count)    (int)(AsciiStrnCmp(string1,string2,(UINTN)(count)))
 #define strcpy(strDest,strSource)         AsciiStrCpy(strDest,strSource)
 #define strncpy(strDest,strSource,count)  AsciiStrnCpy(strDest,strSource,(UINTN)count)

Cryptlib/SysCall/BaseStrings.c

@@ -64,4 +64,32 @@ AsciiStrSize(CHAR8 *string)
 	return strlena(string) + 1;
 }
 
+int
+strcmp (const char *str1, const char *str2)
+{
+	return strcmpa((CHAR8 *)str1,(CHAR8 *)str2);
+}
+
+inline static char
+toupper (char c)
+{
+	return ((c >= 'a' && c <= 'z') ? c - ('a' - 'A') : c);
+}
 
+/* Based on AsciiStriCmp() in edk2 MdePkg/Library/BaseLib/String.c */
+int
+strcasecmp (const char *str1, const char *str2)
+{
+	char c1, c2;
+
+	c1 = toupper (*str1);
+	c2 = toupper (*str2);
+	while ((*str1 != '\0') && (c1 == c2)) {
+		str1++;
+		str2++;
+		c1 = toupper (*str1);
+		c2 = toupper (*str2);
+	}
+
+	return c1 - c2;
+}

Cryptlib/SysCall/CrtWrapper.c

@@ -424,11 +424,6 @@ int stat (const char *c, struct stat *s)
   return -1;
 }
 
-int strcasecmp (const char *c, const char *s)
-{
-  return 0;
-}
-
 int strncasecmp (const char *c, const char *s, size_t l)
 {
   return 0;