When GCC is built bionic's stdio.h (among other headers) is fixed: __va_list
is replaced with __gnuc_va_list, and put in include-fixed/stdio.h,
unless stdio.h already contains __gnuc_va_list. When GCC is later
used bionic's stdio.h is never included.
The problem in the context of NDK is that all 32-bit Android toolchain
are built with android-9 header and expect to work with all API levels
sometime with sustantially different stdio.h.
This CL stops GCC from generating include-fixed/stdio.h by putting
__gnuc_va_list in it.
See bionic df85f50b and b.android.com/73728
Change-Id: I7a490496efbd491a0376608b9ae6e9e2dfc15fb3
