some toolchain provider remove const qualifier from global_impure_ptr
(e.g. Espressif) but other provider keep it(e.g. ARM or Cadence), so
let's define const to empty macro to pass the compile and more safety.
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
to fix the gcov link error:
arm-none-eabi-ld: /home/xiaoxiang/vela/prebuilts/gcc/linux/arm/bin/../lib/gcc/arm-none-eabi/10.3.1/thumb/v7e-m/nofp/libgcov.a(_gcov.o): in function `gcov_error_exit':
libgcov-driver.c:(.text+0x7c): undefined reference to `_impure_ptr'
arm-none-eabi-ld: /home/xiaoxiang/vela/prebuilts/gcc/linux/arm/bin/../lib/gcc/arm-none-eabi/10.3.1/thumb/v7e-m/nofp/libgcov.a(_gcov.o): in function `get_gcov_error_file':
libgcov-driver.c:(.text+0x1e0): undefined reference to `_impure_ptr'
arm-none-eabi-ld: /home/xiaoxiang/vela/prebuilts/gcc/linux/arm/bin/../lib/gcc/arm-none-eabi/10.3.1/thumb/v7e-m/nofp/libgcov.a(_gcov.o): in function `gcov_exit_open_gcda_file.isra.0':
libgcov-driver.c:(.text+0x660): undefined reference to `_impure_ptr'
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
