Hello,
I tried to build mesa-6.2.1 for 64 Biz on solaris 8 with the 
gcc from sunfreeware. 
gcc -v
Reading specs from /usr/local/lib/gcc/sparc-sun-solaris2.8/3.4.2/specs
Configured with: ../configure --with-as=/usr/ccs/bin/as
--with-ld=/usr/ccs/bin/ld --disable-nls --disable-libgcj
--enable-languages=c,c++
Thread model: posix
gcc version 3.4.2

The first problem was that there was just a sunos5-gcc
in ther config directory so I modified sunos5-gcc.
I changed the CFLAGS and CXXFLAGS from 
-O3 -I/usr/openwin/include -fPIC -fomit-frame-pointer -D_REENTRANT -DUSE_XSHM
-DUSE_SPARC_ASM
to
m64 -mcpu=ultrasparc -mvis -O3 -I/usr/openwin/include -fPIC -fomit-frame-pointer
-D_REENTRANT -DUSE_XSHM -DUSE_SPARC_ASM
The next problem are the sparc asembler files clip.S, lapi_sparc.S,
norm.S and xform.S. (On 32 Bit it compiles fine but on 64 Bit
it produces errors:
...
/usr/ccs/bin/as: "/var/tmp//ccoYW8mj.s", line 187: error: detect global register
use not covered .register pseudo-op
/usr/ccs/bin/as: "/var/tmp//ccoYW8mj.s", line 188: warning: detect global
register use not covered .register pseudo-op
/usr/ccs/bin/as: "/var/tmp//ccoYW8mj.s", line 190: error: detect global register
use not covered .register pseudo-op
/usr/ccs/bin/as: "/var/tmp//ccoYW8mj.s", line 190: error: detect global register
use not covered .register pseudo-op
/usr/ccs/bin/as: "/var/tmp//ccoYW8mj.s", line 191: error: detect global register
use not covered .register pseudo-op

So I commented out the #ifdef SVR4 and
used in Clip.S
        .register %g2, #scratch
        .register %g3, #scratch
        .register %g7, #scratch
Ok, now it compiles the files. For linking the shared lib 
64 Bit I had to change bin/mklib
I tried the following:
LINK="gcc"
OPTS="-m64 -shared -Wl,-Bdynamic"
=> for compiling the demos I changed CC to CXX in the Makefiles

and I tried
LINK="gcc"
OPTS="-m64 -G"
Then everything compiled and linked e.g. ldd gears


 but the application ldd
gears                                                            libX11.so.4
=>   /usr/lib/64/libX11.so.4
        libglut.so =>    ../../lib//libglut.so
        libGLU.so =>     ../../lib//libGLU.so
        libGL.so =>      ../../lib//libGL.so
        libstdc++.so.6 =>        /usr/local/lib/sparcv9//libstdc++.so.6
        libm.so.1 =>     /usr/lib/64/libm.so.1
        libgcc_s.so.1 =>         /usr/local/lib/sparcv9//libgcc_s.so.1
        libc.so.1 =>     /usr/lib/64/libc.so.1
        libXext.so.0 =>  /usr/openwin/lib/sparcv9/libXext.so.0
        libsocket.so.1 =>        /usr/lib/64/libsocket.so.1
        libnsl.so.1 =>   /usr/lib/64/libnsl.so.1
        libdl.so.1 =>    /usr/lib/64/libdl.so.1
        libXmu.so.4 =>   /usr/lib/64/libXmu.so.4
        libXi.so.5 =>    /usr/lib/64/libXi.so.5
        libmp.so.2 =>    /usr/lib/64/libmp.so.2
        libXt.so.4 =>    /usr/openwin/lib/sparcv9/libXt.so.4
        libSM.so.6 =>    /usr/openwin/lib/sparcv9/libSM.so.6
        libICE.so.6 =>   /usr/openwin/lib/sparcv9/libICE.so.6
        libICE.so.6 (SUNWprivate) =>     (version not found)
        libICE.so.6 (SUNWprivate) =>     (version not found)
        /usr/platform/SUNW,Ultra-5_10/lib/sparcv9/libc_psr.so.1
file gears
gears:          ELF 64-bit MSB executable SPARCV9 Version 1, UltraSPARC1
Extensions Required, dynamically linked, not stripped
./gears
Illegal instruction (core dumped)

My gdb is not compiled for 64 Bit so I have no call stack
but I think it is a problem with the assembler files.

It would be nice if somebody of the mesa team could try to
compile mesa 64 Bit on Solaris with the gcc 3.4.2 or newer.


crashed after starting