I ported BOINC, SETI and E@H's LIGO apps to SPARC Solaris. Here's the BOINC client. I will post the other clients in their appropriate forums and link them here.

STATUS
BOINC: Verified and published - This Post and https://kulowiec.com/boinc
seti_boinc: Verified and published - https://setiathome.berkeley.edu/forum_thread.php?id=85403#2041598 and https://kulowiec.com/seti
einstein@home: In progress


## boinc ##

cd boinc-client_release-7-7.14
export MAKE=/usr/bin/gmake
export M4=/usr/bin/gm4
alias m4=/usr/bin/gm4
alias make=/usr/bin/gmake
./_autosetup 
gzip -dc boinc_7.14.2_patches.tar.gz | tar xf -
patch configure configure.patch
./configure --disable-server --disable-manager --prefix=/usr/local
patch lib/procinfo_unix.cpp lib/procinfo_unix.cpp.patch
patch client/mac_address.cpp client/mac_address.cpp.patch
gmake -j 96
gmake install

PATCH FILES TEXT
## boinc ##
lib/procinfo_unix.cpp.patch

221c221
<         pm.insert(std::pair(p.id, p));
---
>         pm.insert(std::pair<int,PROCINFO>(p.id, p));

7.15.0
configure.patch

3743c3743
< REV=`echo '$Revision$' | awk "{print $2}"`
---
> REV=`echo '$Revision$' | awk '{print "$2"}'`

7.14.2
configure.patch

3830c3830
< REV=`echo '$Revision$' | awk "{print $2}"`
---
> REV=`echo '$Revision$' | awk '{print "$2"}'`

client/mac_address.cpp.patch

255c255
< #ifdef SIOCGIFHWADDR
---
> #ifdef defined(SIOCGIFHWADDR) &&  (!defined(__sun__))

Interesting!
How does it compare to X86 or ARM?
I suppose only ARM projects will run?

-duplicate, network timeout, please ignore/delete-