4.1/4.2/4.3 PATCH: Switch boehm-gc to pthreads on Solaris (boehm-gc/21940, boehm-gc/21942)

[Andrew Haley]

Rainer Orth writes:
 >
 > Bootstrapped without regressions on sparc-sun-solaris2.10 and
 > i386-pc-solaris2.10 (mainline and 4.2 branch on sparc, 4.2 branch only on
 > x86).   Ok for both (mainline after the lockdown)?

Yes, but make sure you send it upstream to Boehm.

Andrew.