fixed uninstallers processing of /D=

realcmds might point exactly to cmdline, so zeroing cmdline-2 may not affect it
instead, zero cmdline-2, cmdline-1, cmdline and cmdline+1 (entire " /D=")


git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@4967 212acab6-be3b-0410-9dea-997c60f758d6

Source/exehead/Main.c

@@ -140,7 +140,7 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInst,LPSTR lpszCmdParam,
 
       if (*(LPDWORD)(cmdline-2) == CHAR4_TO_DWORD(' ', '/', 'D','='))
       {
-        cmdline[-2]=0; // keep this from being passed to uninstaller if necessary
+        *(LPDWORD)(cmdline-2)=0; // keep this from being passed to uninstaller if necessary
         mystrcpy(state_install_directory,cmdline+2);
         break; // /D= must always be last
       }