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I want to build Rockbox from source for MIPS targets. According their the wiki I need a tool chain with binutils v2.17 and GCC v4.1.2 for the mipsel-elf target with CFLAGS="-U_FORTIFY_SOURCE -fgnu89-inline". Here's the configure line for both:

CFLAGS='-U_FORTIFY_SOURCE -fgnu89-inline' ./configure --target=mipsel-elf --enable-languages=c --disable-libssp --disable-docs

I was able to build and install binutils but GCC fails with both the “automatic build” and the manual method because (also see the full make log):

make[4]: Entering directory `/home/malte/Software/devel/linux-dev/ubuntu/gcc/gcc-4.1.2/host-x86_64-unknown-linux-gnu/gcc'
/home/malte/Software/devel/linux-dev/ubuntu/gcc/gcc-4.1.2/host-x86_64-unknown-linux-gnu/gcc/xgcc -B/home/malte/Software/devel/linux-dev/ubuntu/gcc/gcc-4.1.2/host-x86_64-unknown-linux-gnu/gcc/ -B/usr/local/mipsel-elf/bin/ -B/usr/local/mipsel-elf/lib/ -isystem /usr/local/mipsel-elf/include -isystem /usr/local/mipsel-elf/sys-include -O2 -O2 -U_FORTIFY_SOURCE -fgnu89-inline  -DIN_GCC -DCROSS_COMPILE   -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include  -I. -I. -I../.././gcc -I../.././gcc/. -I../.././gcc/../include -I../.././gcc/../libcpp/include   -g0 -finhibit-size-directive -fno-inline-functions -fno-exceptions -fno-zero-initialized-in-bss -fno-unit-at-a-time -Dinhibit_libc -G 0 \
      -c ../.././gcc/crtstuff.c -DCRT_BEGIN \
      -o crtbegin.o
cc1: error: unrecognized command line option "-fgnu89-inline"
make[4]: *** [crtbegin.o] Error 1

As far as I can tell the issue is that CFLAGS meant for the host compiler are passed to the “minimal” xgcc that's doesn't know or require this flag. Building without -fgnu89-inline fails because GCC 4.1.2 relies on C89 function inline semantics.

Question: How can I configure the build so that -fgnu89-inline is passed to the host compiler but not the minimal compiler during the 2nd phase?

I noticed that the build succeeds if I replace -fgnu89-inline with -std=gnu89 but I don't feel that's right. Cross-compilation for embedded devices is tricky enough and I'd rather not introduce another possible source for errors.

System info:

  • OS: Ubuntu 14.04 (x86_64)
  • Host binutils: 2.26.1-1ubuntu1~16.04.3
  • Host gcc: 6.2.0-3ubuntu11~14.04
  • GNU Make: 3.81
  • Autoconf: 2.13

Bonus: If I add --with-arch=<ANYTHING> to the build configuration I get the a similar error as above:

cc1: error: unrecognized command line option "-march=native"
cc1: error: unrecognized command line option "-fgnu89-inline"
David Foerster
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  • Did you find a solution to your problem? – oPless Aug 23 '17 at 07:10
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    @oPless: No. None besides the work-around described in the question. The resulting GCC appears to do its job though. – David Foerster Aug 23 '17 at 10:03
  • I ended up using an old Ubuntu docker container to build my cross compiler tools 10.04 IIRC. Much fun :) – oPless Aug 24 '17 at 10:51
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    I found 'CFLAGS_FOR_TARGET' can be passed to configure as 'VAR=VALUE' syntax. So, you can use double quotes for multiple options, if your configure supports this. For example, `CFLAGS_FOR_TARGET="-fPIE -O2 -g -mno-pic-data-is-text-relative"` might work for an ARM pc-relative build of libc. – artless noise Aug 17 '22 at 14:13

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