[Clfs-support] Help with cross-compiling glibc toolchain

[Joe Ciccone]

Daniel Jabbour wrote:
> Hi,
>
> I am trying to build a cross-compiled glibc toolchain on a non-linux
> platform. My only issue involves a problem with the include path for
> glibc. I have patched glibc with the cross_hacks patch from your CLFS
> project. This basically makes glibc compile a native localedef-native
> binary so localedata/insatll-locales will work in the cross-compiler.
>
> The issue is that it cannot find libintl.h during compilation. This is
> part of the GNU gettext utilities package. So basically, I know I need
> to figure out some way to get the make script to properly include the
> path to my headers for gettext. On my system, gettext is installed in
> /usr/local/include/.
>
> I have tried two methods to pass the include directory, neither worked.
>
> First, I tried to pass it to the configure script for glibc by way of
> CPPFLAGS. In this case my configure command looked like:
>
> BUILD_CC="gcc" CC="mipsel-linux-gcc" CPPFLAGS="-I/opt/local/include"
> AR="mipsel-linux-ar" RANLIB="mipsel-linux-ranlib"
> ../glibc-2.6.1/configure --prefix=/usr --libexecdir=/usr/lib/glibc
> --host=mipsel-linux --disable-profile --enable-add-ons --with-tls
> --enable-kernel=2.6.0 --with-__thread
> --with-binutils=/opt/mipsel-liunx-toolchain/bin
> --with-headers=../linux-2.6.24.3-lt-headers --cache-file=config.cache
>
> When I did a make, however, it still didn't find libintl.h, and I
> noticed no -I/opt/local/include in the gcc commands that it called.
>
> Next, i tried passing the CPPFLAGS variable to make such as:
> make CPPFLAGS="-I/opt/local/include"
>
> This time, I noticed the -I flag was being passed to gcc, but that the
> native -I flags there used to be there were not. This meant that it
> could no longer find the various other files it needed to include, and
> died on something else.
>
> My conclusion is that CPPFLAGS during `make` overrides all other
> compiler flags, and CPPFLAGS during `configure` is ignored. So how do
> I pass this information to the build process for glibc so I can
> compile it on my system? Thank you kindly,
I would try BUILD_CC="gcc -I/opt/local/include" . I know its not exactly
kosher but it should work. And yes, you're right, when compiling glibc
specifying a flag on the command line does override the variable
completely. That behavior can be very useful in some situations but in
this particular one its more of a pain.

Specifying a variable like CPPFLAGS on the command line wont make it
into the native compile command. I had to add a few make targets
specifically for compiling natively and I did not add CPPFLAGS in
because it probably would create problems to use the same headers for
the host and cross system. Instead CPPFLAGS-native is used.

I just took a look through the patch, It looks like the only way to get
extra options onto the BUILD_CC command would be to append them to the
variable passed to configure. In the patched Makerules file at about
line 365 you'll see:

+native-compile.c = $(BUILD_CC) -g $< -c $(CFLAGS-native) $(CPPFLAGS-native)

Both CFLAGS-native and CPPFLAGS-native are defined to override any
previous settings. (should)