should be safe to set

cmake/stm32_gcc.cmake

@@ -13,3 +13,6 @@ find_program(CMAKE_ASM_COMPILER NAMES ${STM32_TARGET_TRIPLET}-gcc HINTS ${TOOLCH
 set(CMAKE_EXECUTABLE_SUFFIX_C   .elf)
 set(CMAKE_EXECUTABLE_SUFFIX_CXX .elf)
 set(CMAKE_EXECUTABLE_SUFFIX_ASM .elf)
+
+# See: https://cmake.org/cmake/help/latest/variable/CMAKE_FIND_ROOT_PATH_MODE_PROGRAM.html
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)