diff --git a/m4/acx_pthread.m4 b/m4/acx_pthread.m4
index dcd7f26b..a67ba039 100644
--- a/m4/acx_pthread.m4
+++ b/m4/acx_pthread.m4
@@ -57,6 +57,7 @@ acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -m
 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
 #      doesn't hurt to check since this sometimes defines pthreads too;
 #      also defines -D_REENTRANT)
+#      ... -mt is also the pthreads flag for HP/aCC
 # pthread: Linux, etcetera
 # --thread-safe: KAI C++
 # pthread-config: use pthread-config program (for GNU Pth library)
@@ -66,13 +67,13 @@ case "${host_cpu}-${host_os}" in
 
         # On Solaris (at least, for some versions), libc contains stubbed
         # (non-functional) versions of the pthreads routines, so link-based
-        # tests will erroneously succeed.  (We need to link with -pthread or
+        # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
         # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
         # a function called by this macro, so we could check for that, but
         # who knows whether they'll stub that too in a future libc.)  So,
         # we'll just look for -pthreads and -lpthread first:
 
-        acx_pthread_flags="-pthreads pthread -mt $acx_pthread_flags"
+        acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
         ;;
 esac
 
@@ -146,14 +147,14 @@ if test "x$acx_pthread_ok" = xyes; then
         AC_MSG_CHECKING([for joinable pthread attribute])
         attr_name=unknown
         for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
-            AC_TRY_LINK([#include <pthread.h>], [int attr=$attr;],
+            AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],
                         [attr_name=$attr; break])
         done
         AC_MSG_RESULT($attr_name)
         if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
             AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
                                [Define to necessary symbol if this constant
-                               uses a non-standard name on your system.])
+                                uses a non-standard name on your system.])
         fi
 
         AC_MSG_CHECKING([if more special flags are required for pthreads])
@@ -166,13 +167,17 @@ if test "x$acx_pthread_ok" = xyes; then
         if test "x$flag" != xno; then
             PTHREAD_CPPFLAGS="$flag $PTHREAD_CPPFLAGS"
         fi
-        AC_CHECK_TYPES(pthread_rwlock_t,,,[#include <pthread.h>])
 
+        AC_CHECK_FUNCS([pthread_spin_lock])
         LIBS="$save_LIBS"
         CFLAGS="$save_CFLAGS"
 
-        # More AIX lossage: must compile with cc_r
-        AC_CHECK_PROG(PTHREAD_CC, cc_r, cc_r, ${CC})
+        # More AIX lossage: must compile with xlc_r or cc_r
+        if test x"$GCC" != xyes; then
+          AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
+        else
+          PTHREAD_CC=$CC
+        fi
 else
         PTHREAD_CC="$CC"
 fi
diff --git a/m4/vorbis.m4 b/m4/vorbis.m4
index 6401ab6c..17add29b 100644
--- a/m4/vorbis.m4
+++ b/m4/vorbis.m4
@@ -58,16 +58,17 @@ AC_TRY_LINK_FUNC(ogg_stream_init, [xt_lib_vorbis=ok],
             )
         ])
 
-AC_MSG_RESULT([$xt_lib_vorbis])
 if test "x$xt_lib_vorbis" = "xok"; then
 #
 # Now check if the installed Vorbis is sufficiently new.
 #
-AC_CHECK_TYPES([struct ovectl_ratemanage_arg],,
-        [xt_lib_vorbis="old version found"], [
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
 #include <vorbis/codec.h>
 #include <vorbis/vorbisenc.h>
-        ])
+        ], [
+struct ovectl_ratemanage_arg a;
+])],,[xt_lib_vorbis="old version found"])
+AC_MSG_RESULT([$xt_lib_vorbis])
 fi
 CPPFLAGS="$xt_save_CPPFLAGS"
 LIBS="$xt_save_LIBS"
diff --git a/m4/xiph_compiler.m4 b/m4/xiph_compiler.m4
index b80b49cf..e1739c18 100644
--- a/m4/xiph_compiler.m4
+++ b/m4/xiph_compiler.m4
@@ -178,9 +178,9 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM(,[const char *x = __func__;])],
     [ AH_TEMPLATE([__func__], [Replace __func__ if not supported])
     AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[const char *x = __FUNCTION__;])],
         [ AC_DEFINE([__func__],[__FUNCTION__])
-        AC_MSG_RESULT([yes])],
-        [ AC_DEFINE([__func__],[""])
-        AC_MSG_RESULT([no])
+        AC_MSG_RESULT([Using __FUNCTION__])],
+        [ AC_DEFINE([__func__],["__FILE__"])
+        AC_MSG_RESULT([using __FILE__])
         ])
     ])
 ])dnl XIPH_C__FUNC__
diff --git a/m4/xiph_curl.m4 b/m4/xiph_curl.m4
index 9e2786e6..f2b49aaf 100644
--- a/m4/xiph_curl.m4
+++ b/m4/xiph_curl.m4
@@ -9,7 +9,13 @@ dnl Get the cflags and libraries
 dnl
 AC_ARG_WITH(curl,
     AC_HELP_STRING([--with-curl=PFX],[Prefix where libcurl is installed (optional)]),
-    curl_prefix="$withval", curl_prefix="")
+    curl_prefix="$withval", curl_prefix="$CURL_PREFIX")
+
+if test "x$curl_prefix" = "xno"
+then
+  AC_MSG_RESULT([libcurl support disabled by request])
+else
+
 AC_ARG_WITH(curl-config,
     AC_HELP_STRING([--with-curl-config=curl-config],[Use curl-config to find libcurl]),
     CURL_CONFIG="$withval", [AC_PATH_PROGS(CURL_CONFIG, [curl-config], "")])
@@ -66,4 +72,7 @@ else
 fi
 CPPFLAGS="$xt_curl_CPPFLAGS"
 LIBS="$xt_curl_LIBS"
+fi
+AC_SUBST(CURL_CFLAGS)
+AC_SUBST(CURL_LIBS)
 ])