main/gcc4: fix build
Fix the build failure when built with newer gcc:
/home/pmos/build/src/gcc-4.9.2/gcc/reload1.c:89:24: error: use of an operand of type 'bool' in 'operator++' is forbidden in C++17
89 | (this_target_reload->x_spill_indirect_levels)
| ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
/home/pmos/build/src/gcc-4.9.2/gcc/reload1.c:444:7: note: in expansion of macro 'spill_indirect_levels'
444 | spill_indirect_levels++;
| ^~~~~~~~~~~~~~~~~~~~~
Patch source: https://github.com/ChrisMacGregor/esp-open-sdk/blob/master/1001-fix-reload1-compile-error.patch