diff --git a/ase/cmn/makefile.in b/ase/cmn/makefile.in
index a5cdf411..920855ac 100644
--- a/ase/cmn/makefile.in
+++ b/ase/cmn/makefile.in
@@ -5,10 +5,12 @@ C_OBJS = $(C_SRCS:.c=.o)
 
 CC = @CC@
 AR = ar
+MAKE = @MAKE@
 RANLIB = @RANLIB@
 CFLAGS = @CFLAGS@ -I@abs_top_builddir@/..
 LDFLAGS = @LDFLAGS@
 LIBS = @LIBS@
+BUILDMODE = @BUILDMODE@
 
 all: lib 
 
diff --git a/ase/configure b/ase/configure
index 14d5ae22..1233e620 100755
--- a/ase/configure
+++ b/ase/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.ac Revision: 1.77 .
+# From configure.ac Revision: 1.78 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.59 for ase deb-0.1.0.
 #
@@ -309,7 +309,7 @@ ac_includes_default="\
 # include <unistd.h>
 #endif"
 
-ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT RANLIB ac_ct_RANLIB CPP EGREP LIBOBJS LTLIBOBJS'
+ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT RANLIB ac_ct_RANLIB CPP EGREP BUILDMODE LIBOBJS LTLIBOBJS'
 ac_subst_files=''
 
 # Initialize some variables set by options.
@@ -844,6 +844,7 @@ Optional Features:
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
   --enable-wchar          use wchar_t a default charater type when enabled
                           (default. yes)
+  --enable-debug          build the library in the debug mode (default. no)
   --enable-reentrant      define _REENTRANT (default. yes)
 
 Some influential environment variables:
@@ -2320,7 +2321,18 @@ else
 fi
 
 
-# Checks for libraries.
+# Overrides the default CFLAGS setting
+if test "$ac_test_CFLAGS" = "set"
+then
+	CFLAGS=$ac_save_CFLAGS
+else
+	if test "$GCC" = "yes"
+	then
+		CFLAGS="-O2"
+	else
+		CFLAGS=
+	fi
+fi
 
 # Checks for header files.
 
@@ -9869,7 +9881,8 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
-# Checks for library functions.
+# Defines extra options
+
 # Check whether --enable-wchar or --disable-wchar was given.
 if test "${enable_wchar+set}" = set; then
   enableval="$enable_wchar"
@@ -9892,6 +9905,25 @@ _ACEOF
 
 fi
 
+# Check whether --enable-mode or --disable-mode was given.
+if test "${enable_mode+set}" = set; then
+  enableval="$enable_mode"
+  enable_debug_is=$enableval
+else
+  enable_debug_is=no
+fi;
+if test "$enable_debug_is" = "yes"
+then
+	CFLAGS="$CFLAGS -g -D_DEBUG -UNDEBUG"
+	BUILDMODE="debug"
+
+else
+	CFLAGS="$CFLAGS -DNDEBUG -U_DEBUG"
+	BUILDMODE="release"
+
+fi
+
+# Configure makefiles
 # Check whether --enable-reentrant or --disable-reentrant was given.
 if test "${enable_reentrant+set}" = set; then
   enableval="$enable_reentrant"
@@ -10533,6 +10565,7 @@ s,@RANLIB@,$RANLIB,;t t
 s,@ac_ct_RANLIB@,$ac_ct_RANLIB,;t t
 s,@CPP@,$CPP,;t t
 s,@EGREP@,$EGREP,;t t
+s,@BUILDMODE@,$BUILDMODE,;t t
 s,@LIBOBJS@,$LIBOBJS,;t t
 s,@LTLIBOBJS@,$LTLIBOBJS,;t t
 CEOF
diff --git a/ase/configure.ac b/ase/configure.ac
index 2b7c7ce8..78e8d750 100644
--- a/ase/configure.ac
+++ b/ase/configure.ac
@@ -1,6 +1,6 @@
 AC_PREREQ(2.53)
 AC_INIT([ase], [deb-0.1.0])
-AC_REVISION([$Revision: 1.78 $])
+AC_REVISION([$Revision: 1.79 $])
 AC_CONFIG_HEADER([cmn/conf_unx.h])
 
 # Checks for programs.
@@ -8,7 +8,18 @@ AC_CONFIG_HEADER([cmn/conf_unx.h])
 AC_PROG_CC
 AC_PROG_RANLIB
 
-# Checks for libraries.
+# Overrides the default CFLAGS setting
+if test "$ac_test_CFLAGS" = "set"
+then
+	CFLAGS=$ac_save_CFLAGS
+else
+	if test "$GCC" = "yes"
+	then
+		CFLAGS="-O2"
+	else
+		CFLAGS=
+	fi
+fi
 
 # Checks for header files.
 AC_HEADER_STDC
@@ -57,7 +68,8 @@ AC_DEFINE_UNQUOTED(ASE_SIZEOF_DOUBLE,${ac_cv_sizeof_double})
 AC_DEFINE_UNQUOTED(ASE_SIZEOF_LONG_DOUBLE,${ac_cv_sizeof_long_double})
 AC_DEFINE_UNQUOTED(ASE_SIZEOF_WCHAR_T,${ac_cv_sizeof_wchar_t})
 
-# Checks for library functions.
+# Defines extra options
+
 AC_ARG_ENABLE([wchar], [AC_HELP_STRING([--enable-wchar],
 	[use wchar_t a default charater type when enabled (default. yes)])],
 	enable_wchar_is=$enableval,enable_wchar_is=yes)
@@ -68,6 +80,19 @@ else
 	AC_DEFINE([ASE_CHAR_IS_MCHAR],[],[char is mchar])
 fi
 
+AC_ARG_ENABLE([mode], [AC_HELP_STRING([--enable-debug],
+	[build the library in the debug mode (default. no)])],
+	enable_debug_is=$enableval,enable_debug_is=no)
+if test "$enable_debug_is" = "yes"
+then
+	[CFLAGS="$CFLAGS -g -D_DEBUG -UNDEBUG"]
+	AC_SUBST(BUILDMODE, "debug")
+else
+	[CFLAGS="$CFLAGS -DNDEBUG -U_DEBUG"]
+	AC_SUBST(BUILDMODE, "release")
+fi
+
+# Configure makefiles
 AC_ARG_ENABLE([reentrant], [AC_HELP_STRING([--enable-reentrant],
 	[define _REENTRANT (default. yes)])],
 	enable_reentrant_is=$enableval,enable_reentrant_is=yes)