strcmp() fix was broken.

Detail:
  This alternate implementation returned non-zero for equal strings,
    because the tidyup routine failed to stop examining the differing
    words when it found matching zero bytes.
Admin:
  Tested in softload C library, and in Lazarus ROM image.  strcmp()
    appears to be working per spec now.

Version 5.31. Tagged as 'RISC_OSLib-5_31'

VersionASM

@@ -11,14 +11,14 @@
                         GBLS    Module_HelpVersion
                         GBLS    Module_ComponentName
                         GBLS    Module_ComponentPath
-Module_MajorVersion     SETS    "5.30"
-Module_Version          SETA    530
+Module_MajorVersion     SETS    "5.31"
+Module_Version          SETA    531
 Module_MinorVersion     SETS    ""
-Module_Date             SETS    "10 Apr 2001"
-Module_ApplicationDate2 SETS    "10-Apr-01"
-Module_ApplicationDate4 SETS    "10-Apr-2001"
+Module_Date             SETS    "11 Apr 2001"
+Module_ApplicationDate2 SETS    "11-Apr-01"
+Module_ApplicationDate4 SETS    "11-Apr-2001"
 Module_ComponentName    SETS    "RISC_OSLib"
 Module_ComponentPath    SETS    "RiscOS/Sources/Lib/RISC_OSLib"
-Module_FullVersion      SETS    "5.30"
-Module_HelpVersion      SETS    "5.30 (10 Apr 2001)"
+Module_FullVersion      SETS    "5.31"
+Module_HelpVersion      SETS    "5.31 (11 Apr 2001)"
                         END

VersionNum

-/* (5.30)
+/* (5.31)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
  *
  */
-#define Module_MajorVersion_CMHG        5.30
+#define Module_MajorVersion_CMHG        5.31
 #define Module_MinorVersion_CMHG        
-#define Module_Date_CMHG                10 Apr 2001
+#define Module_Date_CMHG                11 Apr 2001
 
-#define Module_MajorVersion             "5.30"
-#define Module_Version                  530
+#define Module_MajorVersion             "5.31"
+#define Module_Version                  531
 #define Module_MinorVersion             ""
-#define Module_Date                     "10 Apr 2001"
+#define Module_Date                     "11 Apr 2001"
 
-#define Module_ApplicationDate2         "10-Apr-01"
-#define Module_ApplicationDate4         "10-Apr-2001"
+#define Module_ApplicationDate2         "11-Apr-01"
+#define Module_ApplicationDate4         "11-Apr-2001"
 
 #define Module_ComponentName            "RISC_OSLib"
 #define Module_ComponentPath            "RiscOS/Sources/Lib/RISC_OSLib"
 
-#define Module_FullVersion              "5.30"
-#define Module_HelpVersion              "5.30 (10 Apr 2001)"
+#define Module_FullVersion              "5.31"
+#define Module_HelpVersion              "5.31 (11 Apr 2001)"

c/string

@@ -265,6 +265,7 @@ strcmp_checkbytes:
         rc = res & -res;
         res = 0xFF;
         for (;;) {
+          if (((w1 | w2) & res) == 0) return 0;
           if (rc & res) return (w1 & res) - (w2 & res);
           w1 >>= 1;
           w2 >>= 1;