On Tue, Oct 26, 2021 at 2:45 PM Richard Purdie via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > During cross compiling, CPP is being set to the target compiler even for > build targets. As an example, when building a cross compiler targetting > mingw, the config.log for libiberty in > build.x86_64-pokysdk-mingw32.i586-poky-linux/build-x86_64-linux/libiberty/config.log > shows: > > configure:3786: checking how to run the C preprocessor > configure:3856: result: x86_64-pokysdk-mingw32-gcc -E > --sysroot=[sysroot]/x86_64-nativesdk-mingw32-pokysdk-mingw32 > configure:3876: x86_64-pokysdk-mingw32-gcc -E > --sysroot=[sysroot]/x86_64-nativesdk-mingw32-pokysdk-mingw32 conftest.c > configure:3876: $? = 0 > > This is libiberty being built for the build environment, not the target one > (i.e. in build-x86_64-linux). As such it should be using the build > environment's > gcc and not the target one. In the mingw case the system headers are quite > different leading to build failures related to not being able to include a > process.h file for pem-unix.c. > > Fix this by using CC_FOR_BUILD instead of CC. Ultimately a CPP_FOR_BUILD > could be defined but CC_FOR_BUILD seems at least more correct and is a simpler > fix.
Since we're using AC_PROG_CPP to find the preprocessor simply assuming that $(CC_FOR_BUILD) -E works looks dangerous? > 2021-10-26 Richard Purdie <richard.pur...@linuxfoundation.org> > > Changelog: > > * Makefile.in: Use CC_FOR_BUILD as CPP for build targets > to avoid host/target contamination > > Signed-off-by: Richard Purdie <richard.pur...@linuxfoundation.org> > --- > Makefile.in | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/Makefile.in b/Makefile.in > index 34b2d89660d..f4815d7e75f 100644 > --- a/Makefile.in > +++ b/Makefile.in > @@ -152,6 +152,7 @@ BUILD_EXPORTS = \ > AR="$(AR_FOR_BUILD)"; export AR; \ > AS="$(AS_FOR_BUILD)"; export AS; \ > CC="$(CC_FOR_BUILD)"; export CC; \ > + CPP="$(CC_FOR_BUILD) -E"; export CPP; \ > CFLAGS="$(CFLAGS_FOR_BUILD)"; export CFLAGS; \ > CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \ > CXX="$(CXX_FOR_BUILD)"; export CXX; \ > -- > 2.32.0 >
