On Monday I've upgraded to from Ubuntu 11.04 (my initial installation) to 11.10 and now I can't build gcc from source anymore. Since I forgot to uninstall the gcc package before the upgrade, Ubuntu replaced my 4.7.0 compiler with it's stable 4.6.1. So I tried to build the SVN sources again, but it fails. I've most recently tried it with SVN revision 180193.

After some time, the build fails with the following message:

/home/raphael/devel/gcc/build/./gcc/xgcc -B/home/raphael/devel/gcc/build/./gcc/ -B/usr/i686-pc-linux-gnu/bin/ -B/usr/i686-pc-linux-gnu/lib/ -isystem /usr/i686-pc-linux-gnu/include -isystem /usr/i686-pc-linux-gnu/sys-include    -g -O2 -O2  -I. -I. -I../../src/gcc -I../../src/gcc/. -I../../src/gcc/../include -I../../src/gcc/../libdecnumber -I../../src/gcc/../libdecnumber/bid -I../libdecnumber -I../../src/gcc/../libgcc -g -O2 -DIN_GCC   -W -Wall -Wwrite-strings -Wcast-qual -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include  -fPIC -g -DHAVE_GTHR_DEFAULT -DIN_LIBGCC2 -fbuilding-libgcc -fno-stack-protector   -I. -I. -I../.././gcc -I../../../src/libgcc -I../../../src/libgcc/. -I../../../src/libgcc/../gcc -I../../../src/libgcc/../include -I../../../src/libgcc/config/libbid -DENABLE_DECIMAL_BID_FORMAT -DHAVE_CC_TLS  -DUSE_TLS -o _ashldi3.o -MT _ashldi3.o -MD -MP -MF _ashldi3.dep -DL_ashldi3 -c ../../../src/libgcc/../gcc/libgcc2.c \
    -fvisibility=hidden -DHIDE_EXPORTS
In file included from /usr/include/stdio.h:28:0,
             from ../../../src/libgcc/../gcc/tsystem.h:88,
             from ../../../src/libgcc/../gcc/libgcc2.c:29:
/usr/include/features.h:323:26: fatal error: bits/predefs.h: File or directory not found.

I've cofigured it with:

~/devel/gcc/build$ ../src/configure --prefix=/usr --enable-languages=c++

And make it with:

~/devel/gcc/build$ make -j4

Just to be sure, I did a rm -rf * in the build directory in case there's some broken stuff inside. Didn't help, though.

That's the backstory. I tried to fix it and searched for the bits/predefs.h. It's inside /usr/include/i386-linux-gnu. I temporarily fixed the problem by doing

~/devel/gcc/build$ C_INCLUDE_PATH=/usr/include/i386-linux-gnu make -j4

Which is only temporary because now gcc complains that it can't find crti.o.

Which i can find in /usr/lib/i386-linux-gnu. Now i could also set C_LIBRARY_PATH - actually it doesn't work - but I feel like I'm fighting the system here. Also, even if it succeeds, my newly built compiler would also not know about the i386-linux-gnu stuff. So I would have to set C_LIBRARY_PATH and C_INCLUDE_PATH before every build of every project I have. I could add it to my .bashrc but that subverts the system even more.

So, how do I tell the build process:

• That there are additional include/lib directories, and
• That it should build a gcc which respects them too?

Edit: I forgot to include the command which causes the above error message. Also I can think of another solution: Copy the stuff from /usr/include/i386-linux-gnu to /usr/include (same thing for /usr/lib/i386-linux-gnu to /usr/lib). But that doesn't feel right, either. Finally, the system's gcc 4.6.1 can compile other applications just fine, except mine, which use C++11 features not present in the 4.6 series.