Skip posix-to-windows conversion when '::' is seen

The substring '::' most likely denotes an IPv6 address, not a path.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

winsup/cygwin/msys2_path_conv.cc

@@ -368,6 +368,11 @@ path_type find_path_start_and_type(const char** src, int recurse, const char* en
             if (it + 1 < end && it[1] == '~')
                 goto skip_p2w;
             break;
+        case ':':
+            // Avoid mangling IPv6 addresses
+            if (it + 1 < end && it[1] == ':')
+                goto skip_p2w;
+            break;
         ++it;
     }
     it = *src;