bzip2recover: Fix buffer overflow for large argv[0].

bzip2recover.c (main) copies argv[0] to a statically sized buffer
without checking whether argv[0] might be too big (> 2000 chars).

This patch comes from Fedora and was originally reported at
https://bugzilla.redhat.com/show_bug.cgi?id=226979

bzip2recover.c

@@ -309,7 +309,8 @@ Int32 main ( Int32 argc, Char** argv )
    UInt32      buffHi, buffLo, blockCRC;
    Char*       p;
 
-   strcpy ( progName, argv[0] );
+   strncpy ( progName, argv[0], BZ_MAX_FILENAME-1);
+   progName[BZ_MAX_FILENAME-1]='\0';
    inFileName[0] = outFileName[0] = 0;
 
    fprintf ( stderr,