Building gcc out-of-tree from latest svn checkout (r165458). configure line: ~/src/gcc/configure --prefix=/home/amit/install/gcc Installing libmpc from sources either in my home dir or in /usr/local produces the following error (in case of installation in home dir, I appended --with-mpc=/home/amit/install/mpc --with-mpc-include=/home/amit/install/mpc/include --with-mpc-lib=/home/amit/install/mpc/lib to the configure line): checking for x86_64-unknown-linux-gnu-gcc... /home/amit/build/gcc/./gcc/xgcc -B/home/amit/build/gcc/./gcc/ -B/home/amit/install/gcc/x86_64-unknown-linux-gnu/bin/ -B/home/amit/install/gcc/x86_64-unknown-linux-gnu/lib/ -isystem /home/amit/install/gcc/x86_64-unknown-linux-gnu/include -isystem /home/amit/install/gcc/x86_64-unknown-linux-gnu/sys-include checking for suffix of object files... configure: error: in `/home/amit/build/gcc/x86_64-unknown-linux-gnu/libgcc': configure: error: cannot compute suffix of object files: cannot compile See `config.log' for more details. make[2]: *** [configure-stage1-target-libgcc] Error 1 The config.log snippet is: gcc version 4.6.0 20101014 (experimental) (GCC) configure:3004: $? = 0 configure:2993: /home/amit/build/gcc/./gcc/xgcc -B/home/amit/build/gcc/./gcc/ -B/home/amit/install/gcc/x86_64-unknown-linux-gnu/bin/ -B/home/amit/install/gcc/x86_64-unknown-linux-gnu/lib/ -isystem /home/amit/install/gcc/x86_64-unknown-linux-gnu/include -isystem /home/amit/install/gcc/x86_64-unknown-linux-gnu/sys-include -V >&5 xgcc: error: unrecognized option '-V' xgcc: fatal error: no input files compilation terminated. configure:3004: $? = 1 configure:2993: /home/amit/build/gcc/./gcc/xgcc -B/home/amit/build/gcc/./gcc/ -B/home/amit/install/gcc/x86_64-unknown-linux-gnu/bin/ -B/home/amit/install/gcc/x86_64-unknown-linux-gnu/lib/ -isystem /home/amit/install/gcc/x86_64-unknown-linux-gnu/include -isystem /home/amit/install/gcc/x86_64-unknown-linux-gnu/sys-include -qversion >&5 xgcc: error: unrecognized option '-qversion' xgcc: fatal error: no input files compilation terminated. configure:3004: $? = 1 configure:3020: /home/amit/build/gcc/./gcc/xgcc -B/home/amit/build/gcc/./gcc/ -B/home/amit/install/gcc/x86_64-unknown-linux-gnu/bin/ -B/home/amit/install/gcc/x86_64-unknown-linux-gnu/lib/ -isystem /home/amit/install/gcc/x86_64-unknown-linux-gnu/include -isystem /home/amit/install/gcc/x86_64-unknown-linux-gnu/sys-include -o conftest -g -O2 conftest.c >&5 /home/amit/build/gcc/./gcc/cc1: error while loading shared libraries: libmpc.so.2: cannot open shared object file: No such file or directory configure:3023: $? = 1 configure:3211: checking for suffix of object files configure:3233: /home/amit/build/gcc/./gcc/xgcc -B/home/amit/build/gcc/./gcc/ -B/home/amit/install/gcc/x86_64-unknown-linux-gnu/bin/ -B/home/amit/install/gcc/x86_64-unknown-linux-gnu/lib/ -isystem /home/amit/install/gcc/x86_64-unknown-linux-gnu/include -isystem /home/amit/install/gcc/x86_64-unknown-linux-gnu/sys-include -c -g -O2 conftest.c >&5 /home/amit/build/gcc/./gcc/cc1: error while loading shared libraries: libmpc.so.2: cannot open shared object file: No such file or directory configure:3237: $? = 1
You need to adjust your runtime linker paths accordingly.
The docs for --with-mpc do mention this: http://gcc.gnu.org/install/configure.html