Where does autoconf/configure look for include files

Question

I'm trying to compile SDL version 1.2 and when I run configure I see a bunch of output, some of which is the configure tool searching for some c/c++ headers:

checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes

Does it look for these include files in the standard order as an unmodified gcc/g++ would? What about (and more importantly to me) the following case: I'm using a toolchain for cross compilation, which contains a pre-configured g++ that only searches within the toolchain, not the standard locations on the host machine?

Answer 1

Does it look for these include files in the standard order as an unmodified gcc/g++ would?

It uses the order built into the toolchain. Options set by the user (e.g. CFLAGS="--sysroot=/some/dir", etc.) also affect the search for headers/libraries.

I'm using a toolchain for cross compilation, which contains a pre-configured g++ that only searches within the toolchain, not the standard locations on the host machine?

As above, it uses the order built into the cross compiler toolchain. So without any user options set it should search only within the cross compiler toolchain for headers/libraries.