CPack escape sequences for CPACK_NSIS_EXTRA_INSTALL_COMMANDS add garbage to escaped sequence within nested escaped quotes
set(CPACK_NSIS_EXTRA_INSTALL_COMMANDS "WriteRegExpandStr \\\" \\\\\" \\\\\" \\\"")
WriteRegExpandStr " \;\" ""
Because of buggy escape handling in CPack, it is impossible to insert a valid command to update the registry via set.
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