Basically the linker can't be started.
Check that this is a valid path, and the DLL exists. Honestly this rather tortured, and should probably be quoted as it contains spaces
c:/development toolbox/embedded sw environment/stmicroelectronics/stm32cubeide_1.0.2/stm32cubeide/plugins/com.st.stm32cube.ide.mcu.externaltools.gnu-tools-for-stm32.7-2018-q2-update.win32_1.0.0.201904181610/tools/bin/../lib/gcc/arm-none-eabi/7.3.1/liblto_plugin-0.dll
c:/development toolbox/embedded sw environment/stmicroelectronics/stm32cubeide_1.0.2/stm32cubeide/plugins/com.st.stm32cube.ide.mcu.externaltools.gnu-tools-for-stm32.7-2018-q2-update.win32_1.0.0.201904181610/tools/bin/gcc/arm-none-eabi/7.3.1/liblto_plugin-0.dll
If it exists, perhaps it has dependencies that don't, or some AV software had enough for the day.
