--- configure.ac
+++ configure.ac
@@ -1,10 +1,10 @@
 # -*- autoconf -*-
 # Process this file with autoconf to produce a configure script.
 
-AC_INIT(configure.ac)
-AM_INIT_AUTOMAKE(specimen, 0.5.2-rc3)
-AM_CONFIG_HEADER(src/config.h)
-
+AC_INIT([specimen], [0.5.2-rc3])
+AC_CONFIG_HEADERS([src/config.h])
+AM_INIT_AUTOMAKE
+m4_include([acx_pthread.m4])
 
 # compilation
 with_debug="no"
@@ -13,9 +13,7 @@
         [enable debugging information, accepting a performance penalty (default is NO)])],
     [if test x$enable_debug = xyes; then with_debug=yes ; fi])
 
-if test x$with_debug = xno; then
-    CFLAGS="-O3"
-else
+if test x$with_debug != xno; then
     AC_DEFINE(DEBUG, 1, [[whether to display debugging output or not]])
 fi
 
@@ -48,13 +46,14 @@
 AC_FUNC_MALLOC
 AC_CHECK_FUNCS([floor gettimeofday pow strchr strdup])
 
+dnl Check for libm for sin()
+AC_SEARCH_LIBS([sin], [m], [], [
+	AC_MSG_ERROR([unable to find the sin() function])
+])
+
 # pthreads
 ACX_PTHREAD
 
-SPECIMEN_CFLAGS="-Wall -Werror"
-AC_SUBST(SPECIMEN_CFLAGS)
-CFLAGS="$SPECIMEN_CFLAGS $CFLAGS" 
-
 config_error="no"
 
 # gtk			   

--- src/Makefile.am
+++ src/Makefile.am
@@ -11,7 +11,7 @@
 specimen_SOURCES += lashdriver.c lashdriver.h                                                                                                                           
 endif
 
-INCLUDES = \
+AM_CPPFLAGS = \
 	@ALSA_CFLAGS@ \
 	@JACK_CFLAGS@ \
 	@LIBSAMPLERATE_CFLAGS@ \

--- src/gui/Makefile.am
+++ src/gui/Makefile.am
@@ -12,14 +12,14 @@
 paramselector.c paramselector.h patchlist.c patchlist.h midisection.c	\
 midisection.h channelsection.c channelsection.h
 
-INCLUDES = \
+AM_CPPFLAGS = \
 	-l.. \
 	@GTK_CFLAGS@ \
 	@LIBGNOMECANVAS_CFLAGS@ \
 	@PHAT_CFLAGS@
 
 if HAVE_LASH
-INCLUDES += @LASH_CFLAGS@
+AM_CPPFLAGS += @LASH_CFLAGS@
 endif
 
 libgui_a_CFLAGS = $(CFLAGS) -I.. -DINSTALLDIR=\"$(datadir)\"