--- libvorbis-1.3.5/configure.ac~	2015-01-12 21:00:37.000000000 +0100
+++ libvorbis-1.3.5/configure.ac	2015-03-03 12:54:34.168894342 +0100
@@ -128,9 +128,9 @@
 	case $host in 
 	*86-*-linux*)
 		DEBUG="-g -Wall -Wextra -D_REENTRANT -D__NO_MATH_INLINES -fsigned-char"
-		CFLAGS="-O3 -ffast-math -mno-ieee-fp -D_REENTRANT -fsigned-char"
+		CFLAGS="${CFLAGS} -ffast-math -mno-ieee-fp -D_REENTRANT -fsigned-char"
 #              	PROFILE="-Wall -Wextra -pg -g -O3 -ffast-math -D_REENTRANT -fsigned-char -fno-inline -static"
-		PROFILE="-Wall -Wextra -pg -g -O3 -ffast-math -mno-ieee-fp -D_REENTRANT -fsigned-char -fno-inline"
+		PROFILE="-Wall -Wextra -pg -g ${CFLAGS} -ffast-math -mno-ieee-fp -D_REENTRANT -fsigned-char -fno-inline"
 
 		# glibc < 2.1.3 has a serious FP bug in the math inline header
 		# that will cripple Vorbis.  Look to see if the magic FP stack
@@ -181,8 +181,8 @@
 		PROFILE="-pg -g -O3 -ffast-math -mfused-madd -mcpu=750 -D_REENTRANT";;
 	*-*-linux*)
 		DEBUG="-g -Wall -Wextra -D_REENTRANT -D__NO_MATH_INLINES -fsigned-char"
-		CFLAGS="-O3 -Wall -Wextra -ffast-math -D_REENTRANT -fsigned-char"
-		PROFILE="-pg -g -O3 -ffast-math -D_REENTRANT -fsigned-char";;
+		CFLAGS="${CFLAGS} -Wall -Wextra -ffast-math -D_REENTRANT -fsigned-char"
+		PROFILE="-pg -g ${CFLAGS} -ffast-math -D_REENTRANT -fsigned-char";;
 	sparc-sun-*)
 		sparc_cpu=""
 		AC_MSG_CHECKING([if gcc supports -mv8])