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+See README.alpha for Linux on DEC AXP info.  This file applies to
+Linux/Intel.
+
+Incremental GC is supported.
+
+Dynamic libraries are supported on an ELF system.  A static executable
+should be linked with the gcc option "-Wl,-defsym,_DYNAMIC=0".
+
+The collector appears to work with Linux threads.  We have seen
+intermittent hangs in sem_wait.  So far we have been unable to reproduce
+these unless the process was being debugged or traced.  Thus it's
+possible that the only real issue is that the debugger loses
+signals on rare occasions.
+
+The garbage collector uses SIGPWR and SIGXCPU if it is used with
+Linux threads.  These should not be touched by the client program.
+
+To use threads, you need to abide by the following requirements:
+
+1) You need to use LinuxThreads (which are included in libc6).
+
+   The collector relies on some implementation details of the LinuxThreads
+   package.  It is unlikely that this code will work on other
+   pthread implementations (in particular it will *not* work with
+   MIT pthreads).
+
+2) You must compile the collector with -DLINUX_THREADS and -D_REENTRANT
+   specified in the Makefile.
+
+3) Every file that makes thread calls should define LINUX_THREADS and 
+   _REENTRANT and then include gc.h.  Gc.h redefines some of the
+   pthread primitives as macros which also provide the collector with
+   information it requires.
+
+4) Currently dlopen() is probably not safe.  The collector must traverse
+   the list of libraries maintained by the runtime loader.  That can
+   probably be an inconsistent state when a thread calling the loader is
+   is stopped for GC.  (It's possible that this is fixable in the
+   same way it is handled for SOLARIS_THREADS, with GC_dlopen.)