Do not override CFLAGS, as CFLAGS is a user flag.

* Furthermore, use NDEBUG globally to detect the presence
  of building with more debug output information.
  AX_CHECK_ENABLE_DEBUG is easier to use, and nowadays
  Gnome has also switched to it from its own custom solution.
Signed-off-by: Erik de Castro Lopo <erikd@mega-nerd.com>

configure.ac

@@ -26,6 +26,13 @@ AC_CONFIG_MACRO_DIR([m4])
 AM_INIT_AUTOMAKE([foreign 1.10 -Wall tar-pax no-dist-gzip dist-xz subdir-objects])
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 
+AC_MSG_CHECKING([whether configure should try to set CFLAGS/CXXFLAGS/CPPFLAGS/LDFLAGS])
+AS_IF([test "x${CFLAGS+set}" = "xset" || test "x${CXXFLAGS+set}" = "xset" || test "x${CPPFLAGS+set}" = "xset" || test "x${LDFLAGS+set}" = "xset"],
+	[enable_flags_setting=no],
+	[enable_flags_setting=yes]
+)
+AC_MSG_RESULT([${enable_flags_setting}])
+AX_CHECK_ENABLE_DEBUG
 user_cflags=$CFLAGS
 
 #Prefer whatever the current ISO standard is.
@@ -206,14 +213,7 @@ AC_DEFINE(FLAC__ALIGN_MALLOC_DATA)
 AH_TEMPLATE(FLAC__ALIGN_MALLOC_DATA, [define to align allocated memory on 32-byte boundaries])
 fi
 
-AC_ARG_ENABLE(debug,
-AC_HELP_STRING([--enable-debug], [Turn on debugging]),
-[case "${enableval}" in
-	yes) debug=true ;;
-	no)  debug=false ;;
-	*) AC_MSG_ERROR(bad value ${enableval} for --enable-debug) ;;
-esac],[debug=false])
-AM_CONDITIONAL(DEBUG, test "x$debug" = xtrue)
+AM_CONDITIONAL([DEBUG], [test "x${ax_enable_debug}" = "xyes" || test "x${ax_enable_debug}" = "xinfo"])
 
 AC_ARG_ENABLE(sse,
 AC_HELP_STRING([--disable-sse], [Disable passing of -msse2 to the compiler]),
@@ -390,14 +390,13 @@ AC_DEFINE(FLAC__HAS_NASM)
 AH_TEMPLATE(FLAC__HAS_NASM, [define if you are compiling for x86 and have the NASM assembler])
 fi
 
-if test "x$debug" = xtrue; then
-	CPPFLAGS="-DDEBUG $CPPFLAGS"
-	CFLAGS="-g $CFLAGS"
-else
-	CPPFLAGS="-DNDEBUG $CPPFLAGS"
-	CFLAGS=$(echo "$CFLAGS" | sed 's/-O2//')
+dnl If debugging is disabled AND no CFLAGS/CXXFLAGS/CPPFLAGS/LDFLAGS
+dnl are provided, we can set defaults to our liking
+AS_IF([test "x${ax_enable_debug}" = "xno" && test "x${enable_flags_setting}" = "xyes"], [
+	AC_PROG_SED
+	CFLAGS=$(echo "$CFLAGS" | $SED 's/-O2//')
 	CFLAGS="-O3 -funroll-loops $CFLAGS"
-fi
+])
 
 XIPH_GCC_VERSION
 
@@ -406,7 +405,28 @@ if test x$ac_cv_c_compiler_gnu = xyes ; then
 	CXXFLAGS="$CXXFLAGS -Wall -Wextra -Wcast-align -Wshadow -Wwrite-strings -Wctor-dtor-privacy -Wnon-virtual-dtor -Wreorder -Wsign-promo -Wundef " # -Wcast-qual -Wbad-function-cast -Wwrite-strings -Woverloaded-virtual -Wmissing-declarations
 
 	XIPH_ADD_CFLAGS([-Wdeclaration-after-statement])
-	XIPH_ADD_CFLAGS([-D_FORTIFY_SOURCE=2])
+
+	dnl some distributions (such as Gentoo) have _FORTIFY_SOURCE always
+	dnl enabled. We test for this situation in order to prevent polluting
+	dnl the console with messages of macro redefinitions.
+	AC_MSG_CHECKING([whether to add -D_FORTIFY_SOURCE=2 to CFLAGS])
+	AC_LINK_IFELSE([
+		AC_LANG_SOURCE(
+			[[
+				int main() {
+				#ifndef _FORTIFY_SOURCE
+					return 0;
+				#else
+					this_is_an_error;
+				#endif
+				}
+			]]
+		)], [
+			AC_MSG_RESULT([yes])
+			XIPH_ADD_CFLAGS([-D_FORTIFY_SOURCE=2])
+		], [
+			AC_MSG_RESULT([no])
+		])
 
 	AC_LANG_PUSH([C++])
 	XIPH_ADD_CXXFLAGS([-Weffc++])

include/FLAC/assert.h

@@ -34,7 +34,7 @@
 #define FLAC__ASSERT_H
 
 /* we need this since some compilers (like MSVC) leave assert()s on release code (and we don't want to use their ASSERT) */
-#ifdef DEBUG
+#ifndef NDEBUG
 #include <assert.h>
 #define FLAC__ASSERT(x) assert(x)
 #define FLAC__ASSERT_DECLARATION(x) x

m4/ax_check_enable_debug.m4

+# ===========================================================================
+#   http://www.gnu.org/software/autoconf-archive/ax_check_enable_debug.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CHECK_ENABLE_DEBUG([enable by default=yes/info/profile/no], [ENABLE DEBUG VARIABLES ...], [DISABLE DEBUG VARIABLES NDEBUG ...], [IS-RELEASE])
+#
+# DESCRIPTION
+#
+#   Check for the presence of an --enable-debug option to configure, with
+#   the specified default value used when the option is not present.  Return
+#   the value in the variable $ax_enable_debug.
+#
+#   Specifying 'yes' adds '-g -O0' to the compilation flags for all
+#   languages. Specifying 'info' adds '-g' to the compilation flags.
+#   Specifying 'profile' adds '-g -pg' to the compilation flags and '-pg' to
+#   the linking flags. Otherwise, nothing is added.
+#
+#   Define the variables listed in the second argument if debug is enabled,
+#   defaulting to no variables.  Defines the variables listed in the third
+#   argument if debug is disabled, defaulting to NDEBUG.  All lists of
+#   variables should be space-separated.
+#
+#   If debug is not enabled, ensure AC_PROG_* will not add debugging flags.
+#   Should be invoked prior to any AC_PROG_* compiler checks.
+#
+#   IS-RELEASE can be used to change the default to 'no' when making a
+#   release.  Set IS-RELEASE to 'yes' or 'no' as appropriate. By default, it
+#   uses the value of $ax_is_release, so if you are using the AX_IS_RELEASE
+#   macro, there is no need to pass this parameter.
+#
+#     AX_IS_RELEASE([git-directory])
+#     AX_CHECK_ENABLE_DEBUG()
+#
+# LICENSE
+#
+#   Copyright (c) 2011 Rhys Ulerich <rhys.ulerich@gmail.com>
+#   Copyright (c) 2014, 2015 Philip Withnall <philip@tecnocode.co.uk>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved.
+
+#serial 5
+
+AC_DEFUN([AX_CHECK_ENABLE_DEBUG],[
+    AC_BEFORE([$0],[AC_PROG_CC])dnl
+    AC_BEFORE([$0],[AC_PROG_CXX])dnl
+    AC_BEFORE([$0],[AC_PROG_F77])dnl
+    AC_BEFORE([$0],[AC_PROG_FC])dnl
+
+    AC_MSG_CHECKING(whether to enable debugging)
+
+    ax_enable_debug_default=m4_tolower(m4_normalize(ifelse([$1],,[no],[$1])))
+    ax_enable_debug_is_release=m4_tolower(m4_normalize(ifelse([$4],,
+                                                              [$ax_is_release],
+                                                              [$4])))
+
+    # If this is a release, override the default.
+    AS_IF([test "$ax_enable_debug_is_release" = "yes"],
+      [ax_enable_debug_default="no"])
+
+    m4_define(ax_enable_debug_vars,[m4_normalize(ifelse([$2],,,[$2]))])
+    m4_define(ax_disable_debug_vars,[m4_normalize(ifelse([$3],,[NDEBUG],[$3]))])
+
+    AC_ARG_ENABLE(debug,
+	[AS_HELP_STRING([--enable-debug=]@<:@yes/info/profile/no@:>@,[compile with debugging])],
+	[],enable_debug=$ax_enable_debug_default)
+
+    # empty mean debug yes
+    AS_IF([test "x$enable_debug" = "x"],
+      [enable_debug="yes"])
+
+    # case of debug
+    AS_CASE([$enable_debug],
+      [yes],[
+	AC_MSG_RESULT(yes)
+	CFLAGS="${CFLAGS} -g -O0"
+	CXXFLAGS="${CXXFLAGS} -g -O0"
+	FFLAGS="${FFLAGS} -g -O0"
+	FCFLAGS="${FCFLAGS} -g -O0"
+	OBJCFLAGS="${OBJCFLAGS} -g -O0"
+      ],
+      [info],[
+	AC_MSG_RESULT(info)
+	CFLAGS="${CFLAGS} -g"
+	CXXFLAGS="${CXXFLAGS} -g"
+	FFLAGS="${FFLAGS} -g"
+	FCFLAGS="${FCFLAGS} -g"
+	OBJCFLAGS="${OBJCFLAGS} -g"
+      ],
+      [profile],[
+	AC_MSG_RESULT(profile)
+	CFLAGS="${CFLAGS} -g -pg"
+	CXXFLAGS="${CXXFLAGS} -g -pg"
+	FFLAGS="${FFLAGS} -g -pg"
+	FCFLAGS="${FCFLAGS} -g -pg"
+	OBJCFLAGS="${OBJCFLAGS} -g -pg"
+	LDFLAGS="${LDFLAGS} -pg"
+      ],
+      [
+	AC_MSG_RESULT(no)
+	dnl Ensure AC_PROG_CC/CXX/F77/FC/OBJC will not enable debug flags
+	dnl by setting any unset environment flag variables
+	AS_IF([test "x${CFLAGS+set}" != "xset"],
+	  [CFLAGS=""])
+	AS_IF([test "x${CXXFLAGS+set}" != "xset"],
+	  [CXXFLAGS=""])
+	AS_IF([test "x${FFLAGS+set}" != "xset"],
+	  [FFLAGS=""])
+	AS_IF([test "x${FCFLAGS+set}" != "xset"],
+	  [FCFLAGS=""])
+	AS_IF([test "x${OBJCFLAGS+set}" != "xset"],
+	  [OBJCFLAGS=""])
+      ])
+
+    dnl Define various variables if debugging is disabled.
+    dnl assert.h is a NOP if NDEBUG is defined, so define it by default.
+    AS_IF([test "x$enable_debug" = "xyes"],
+      [m4_map_args_w(ax_enable_debug_vars, [AC_DEFINE(], [,,[Define if debugging is enabled])])],
+      [m4_map_args_w(ax_disable_debug_vars, [AC_DEFINE(], [,,[Define if debugging is disabled])])])
+    ax_enable_debug=$enable_debug
+])

src/libFLAC/cpu.c

@@ -47,7 +47,7 @@
 #  include <cpuid.h> /* for __get_cpuid() and __get_cpuid_max() */
 #endif
 
-#ifdef DEBUG
+#ifndef NDEBUG
 #include <stdio.h>
 
 #define dfprintf fprintf

src/libFLAC/lpc.c

@@ -42,7 +42,7 @@
 #include "private/bitmath.h"
 #include "private/lpc.h"
 #include "private/macros.h"
-#if defined DEBUG || defined FLAC__OVERFLOW_DETECT || defined FLAC__OVERFLOW_DETECT_VERBOSE
+#if !defined(NDEBUG) || defined FLAC__OVERFLOW_DETECT || defined FLAC__OVERFLOW_DETECT_VERBOSE
 #include <stdio.h>
 #endif
 
@@ -234,7 +234,7 @@ int FLAC__lpc_quantize_coefficients(const FLAC__real lp_coeff[], uint32_t order,
 		const int nshift = -(*shift);
 		double error = 0.0;
 		FLAC__int32 q;
-#ifdef DEBUG
+#ifndef NDEBUG
 		fprintf(stderr,"FLAC__lpc_quantize_coefficients: negative shift=%d order=%u cmax=%f\n", *shift, order, cmax);
 #endif
 		for(i = 0; i < order; i++) {

src/libFLAC/stream_encoder.c

@@ -3452,7 +3452,7 @@ FLAC__bool process_subframe_(
 #endif
 					rice_parameter++; /* to account for the signed->uint32_t conversion during rice coding */
 					if(rice_parameter >= rice_parameter_limit) {
-#ifdef DEBUG_VERBOSE
+#ifndef NDEBUG
 						fprintf(stderr, "clipping rice_parameter (%u -> %u) @0\n", rice_parameter, rice_parameter_limit - 1);
 #endif
 						rice_parameter = rice_parameter_limit - 1;
@@ -3524,7 +3524,7 @@ FLAC__bool process_subframe_(
 								rice_parameter = (lpc_residual_bits_per_sample > 0.0)? (uint32_t)(lpc_residual_bits_per_sample+0.5) : 0; /* 0.5 is for rounding */
 								rice_parameter++; /* to account for the signed->uint32_t conversion during rice coding */
 								if(rice_parameter >= rice_parameter_limit) {
-#ifdef DEBUG_VERBOSE
+#ifndef NDEBUG
 									fprintf(stderr, "clipping rice_parameter (%u -> %u) @1\n", rice_parameter, rice_parameter_limit - 1);
 #endif
 									rice_parameter = rice_parameter_limit - 1;
@@ -4156,7 +4156,7 @@ FLAC__bool set_partitioned_rice_(
 				min_rice_parameter = suggested_rice_parameter - rice_parameter_search_dist;
 			max_rice_parameter = suggested_rice_parameter + rice_parameter_search_dist;
 			if(max_rice_parameter >= rice_parameter_limit) {
-#ifdef DEBUG_VERBOSE
+#ifndef NDEBUG
 				fprintf(stderr, "clipping rice_parameter (%u -> %u) @5\n", max_rice_parameter, rice_parameter_limit - 1);
 #endif
 				max_rice_parameter = rice_parameter_limit - 1;
@@ -4246,7 +4246,7 @@ FLAC__bool set_partitioned_rice_(
 			}
 #endif
 			if(rice_parameter >= rice_parameter_limit) {
-#ifdef DEBUG_VERBOSE
+#ifndef NDEBUG
 				fprintf(stderr, "clipping rice_parameter (%u -> %u) @6\n", rice_parameter, rice_parameter_limit - 1);
 #endif
 				rice_parameter = rice_parameter_limit - 1;
@@ -4261,7 +4261,7 @@ FLAC__bool set_partitioned_rice_(
 					min_rice_parameter = rice_parameter - rice_parameter_search_dist;
 				max_rice_parameter = rice_parameter + rice_parameter_search_dist;
 				if(max_rice_parameter >= rice_parameter_limit) {
-#ifdef DEBUG_VERBOSE
+#ifndef NDEBUG
 					fprintf(stderr, "clipping rice_parameter (%u -> %u) @7\n", max_rice_parameter, rice_parameter_limit - 1);
 #endif
 					max_rice_parameter = rice_parameter_limit - 1;

src/plugin_common/Makefile.am

@@ -37,9 +37,3 @@ libplugin_common_la_SOURCES = \
 EXTRA_DIST = \
 	Makefile.lite \
 	README
-
-debug:
-	$(MAKE) all CFLAGS="@DEBUG@"
-
-profile:
-	$(MAKE) all CFLAGS="@PROFILE@"

src/plugin_common/charset.c

@@ -75,7 +75,7 @@ char* FLAC_plugin__charset_convert_string (const char *string, char *from, char
 
 	if ((cd = iconv_open(to, from)) == (iconv_t)-1)
 	{
-#ifdef DEBUG
+#ifndef NDEBUG
 		fprintf(stderr, "convert_string(): Conversion not supported. Charsets: %s -> %s", from, to);
 #endif
 		return strdup(string);
@@ -115,7 +115,7 @@ retry:
 				length = strlen(input);
 				goto retry;
 			default:
-#ifdef DEBUG
+#ifndef NDEBUG
 				fprintf(stderr, "convert_string(): Conversion failed. Inputstring: %s; Error: %s", string, strerror(errno));
 #endif
 				break;

src/plugin_xmms/http.c

@@ -61,8 +61,6 @@ static gint icy_metaint = 0;
 
 extern InputPlugin flac_ip;
 
-#undef DEBUG_UDP
-
 /* Static udp channel functions */
 static int udp_establish_listener (gint *sock);
 static int udp_check_for_data(gint sock);
@@ -573,7 +571,7 @@ static int http_connect (gchar *url_, gboolean head, guint64 offset)
 							if (!strncmp(line, "icy-metaint:", 12))
 								icy_metaint = atoi(line + 12);
 							if (!strncmp(line, "x-audiocast-udpport:", 20)) {
-#ifdef DEBUG_UDP
+#ifndef NDEBUG
 								fprintf (stderr, "Server wants udp messages on port %d\n", atoi (line + 20));
 #endif
 								/*udp_serverport = atoi (line + 20);*/
@@ -752,7 +750,7 @@ static int udp_establish_listener(int *sock)
 	struct sockaddr_in sin;
 	socklen_t sinlen = sizeof (struct sockaddr_in);
 
-#ifdef DEBUG_UDP
+#ifndef NDEBUG
 	fprintf (stderr,"Establishing udp listener\n");
 #endif
 
@@ -791,7 +789,7 @@ static int udp_establish_listener(int *sock)
 		return -1;
 	}
 
-#ifdef DEBUG_UDP
+#ifndef NDEBUG
 	fprintf (stderr,"Listening on local %s:%d\n", inet_ntoa(sin.sin_addr), g_ntohs(sin.sin_port));
 #endif
 
@@ -820,7 +818,7 @@ static int udp_check_for_data(int sock)
 		return 0;
 	}
 	buf[len] = '\0';
-#ifdef DEBUG_UDP
+#ifndef NDEBUG
 	fprintf (stderr,"Received: [%s]\n", buf);
 #endif
 	lines = g_strsplit(buf, "\n", 0);
@@ -889,7 +887,7 @@ static int udp_check_for_data(int sock)
 				g_log(NULL, G_LOG_LEVEL_WARNING,
 				      "udp_check_for_data(): Unable to send ack to server: %s", strerror(errno));
 			}
-#ifdef DEBUG_UDP
+#ifndef NDEBUG
 			else
 				fprintf(stderr,"Sent ack: %s", obuf);
 			fprintf (stderr,"Remote: %s:%d\n", inet_ntoa(from.sin_addr), g_ntohs(from.sin_port));

src/share/Makefile.am

@@ -92,9 +92,3 @@ replaygain_analysis_libreplaygain_analysis_la_SOURCES = replaygain_analysis/repl
 
 replaygain_synthesis_libreplaygain_synthesis_la_CFLAGS = -I $(top_srcdir)/src/share/replaygain_synthesis/include
 replaygain_synthesis_libreplaygain_synthesis_la_SOURCES = replaygain_synthesis/replaygain_synthesis.c
-
-debug:
-	$(MAKE) all CFLAGS="@DEBUG@"
-
-profile:
-	$(MAKE) all CFLAGS="@PROFILE@"