install gcc 3.0.4 & 2.95.3 parallel

[Christian Bayer <christian_bay at gmx dot de>]

hello!

my name is christian bayer.

i have got a problem on building a running system with 2 seperate gcc 
compilers. i want to use both gcc 2.95.3 and gcc 3.0.4, so i read the manuals 
and tried to compile both. first gcc 2.95.3, then gcc 3.0.4.
the compiling of both worked, and after installing gcc 2.95.3 i could compile 
a small c-prog. but after installing gcc 2.95.3 and invoking the old compiler 
with "gcc -V 2.95.3" on the same file i just get something like "undefined or 
invalid # directive" for "#include" for example.
gcc 3.0.4 works fine, and compiles the file correctly...but gcc 2.95.3 
doesn't want to work.
any configure-script reports that gcc isn't able to generate binaries. 
(checking whether the C compiler (gcc -V 2.95.3 ) works... no configure: 
error: installation or configuration problem: C compiler cannot create 
executables.)

i tried the following compiling options for both compilers, everytime the 
same fault:

1) ../gcc-3.0.4/configure --prefix=/usr --enable-shared --enable-threads=posix
make bootstrap

2) ../gcc-3.0.4/configure --prefix=/usr --enable-shared 
--enable-threads=posix
make bootstrap-lean

3) ../gcc-3.0.4/configure --prefix=/usr --enable-shared 
--enable-threads=posix --enable-version-specific-runtime-libs  
make CFLAGS='-O' LIBCFLAGS='-g -O2' LIBCXXFLAGS='-g -O2 
-fno-implicit-templates' bootstrap

4)../gcc-3.0.4/configure --prefix=/usr --enable-shared --enable-threads=posix 
--enable-version-specific-runtime-libs
make CFLAGS='-O' LIBCFLAGS='-g -O2' LIBCXXFLAGS='-g -O2 
-fno-implicit-templates' bootstrap-lean

5)../gcc-3.0.4/configure --prefix=/usr --enable-shared --enable-threads=posix 
--enable-version-specific-runtime-libs  
--with-gxx-include-dir=/usr/lib/gcc-lib/i686-pc-linux-gnu/2.95.3/include/g++
make CFLAGS='-O' LIBCFLAGS='-g -O2' LIBCXXFLAGS='-g -O2 
-fno-implicit-templates' bootstrap-lean