This patch fix a potential problem using large strings (NSIS_MAX_STRLEN > 1024) with nsExec plugin.
Despite the increased length the command line is truncated to 1024 bytes.
This is caused by a fixed-size buffer used in WinMain function.
This patch can be applied to version 2.46 sources skipping 1 path element
dynamically allocates WinMain command line buffer in nsexec.c