Bug#649641: pulseaudio mutex issue on Alpha architecture

[Bob Tracy]

Verified that the previously-mentioned workaround is applicable to
Alpha, and that it works: no more mutex failures.  The specific
implementation of the workaround for the 1.1-1 source package is to
patch "m4/ax_pthread.m4" line 266ff to read as follows:

        AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
            ax_cv_PTHREAD_PRIO_INHERIT, [
                AC_LINK_IFELSE(
                    AC_LANG_PROGRAM([[#include <pthread.h>]], [[int i = PTHREAD_PRIO_INHERIT;]]),
                    [ax_cv_PTHREAD_PRIO_INHERIT=no],
                    [ax_cv_PTHREAD_PRIO_INHERIT=no])
            ])

i.e., "ax_cv_PTHREAD_PRIO_INHERIT" gets set to "no" regardless of
whether the test program compiles successfully (which it does on Alpha).