I try to compile gcc-4.2.2 and get these errors:
I use gcc-4.1 on Kubuntu.


WARNING: `bison' missing on your system. You should only need it if
you modified a `.y' file. You may need the `Bison' package
in order for those modifications to take effect. You can get
`Bison' from any GNU archive site.
/home/ulf/GCC/gcc-4.2.2/host-i686-pc-linux-gnu/prev-gcc/xgcc -B/home/ulf/GCC/gcc-4.2.2/host-i686-pc-linux-gnu/prev-gcc/ -B/usr/local/i686-pc-linux-gnu/bin/ -c -O2 -g -fomit-frame-pointer -DIN_GCC -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Wold-style-definition -Wmissing-format-attribute -Wno-error -DHAVE_CONFIG_H -I. -Ijava -I../.././gcc -I../.././gcc/java -I../.././gcc/../include -I../.././gcc/../libcpp/include -I../.././gcc/../libdecnumber -I../libdecnumber java/parse-scan.c -o java/parse-scan.o
xgcc: java/parse-scan.c: No such file or directory
xgcc: no input files
make[3]: *** [java/parse-scan.o] Error 1
make[3]: Leaving directory `/home/ulf/GCC/gcc-4.2.2/host-i686-pc-linux-gnu/gcc'
make[2]: *** [all-stage2-gcc] Error 2
make[2]: Leaving directory `/home/ulf/GCC/gcc-4.2.2'
make[1]: *** [stage2-bubble] Error 2
make[1]: Leaving directory `/home/ulf/GCC/gcc-4.2.2'

WARNING: `bison' missing on your system. You should only need it if
you modified a `.y' file. You may need the `Bison' package
in order for those modifications to take effect. You can get
`Bison' from any GNU archive site.

That said, compiling gcc can be a right pain, it's very finickity. I recommend a double vodka before sitting down to try. It takes the edge off the pain.

j think it is trying to rebuild a c file from a yacc file so i think you need to install bison.