The sed expression is wrong, any flags with '-g' in any position gets
zapped, for example:

-mfloat-gprs=double (for powerpc e500) -> -mfloatprs=double.

Which gives build errors and is perfectly valid in real use scenarios to
switch from e500v1 (single precision) code to e500v2 (double precision) code.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>

diff -Nura flac-1.3.1.orig/configure flac-1.3.1/configure
--- flac-1.3.1.orig/configure	2014-11-27 20:43:29.921303105 -0300
+++ flac-1.3.1/configure	2014-11-27 20:45:33.460250179 -0300
@@ -19870,11 +19870,10 @@
 
 if test "x$debug" = xtrue; then
 	CPPFLAGS="-DDEBUG $CPPFLAGS"
-	CFLAGS=$(echo "$CFLAGS" | sed 's/-g//')
-	CFLAGS="-g $CFLAGS"
+	CFLAGS=$(echo "-g $CFLAGS")
 else
 	CPPFLAGS="-DNDEBUG $CPPFLAGS"
-	CFLAGS=$(echo "$CFLAGS" | sed 's/-O2//;s/-g//')
+	CFLAGS=$(echo "$CFLAGS" | sed 's/-O2//')
 	CFLAGS="-O3 -funroll-loops $CFLAGS"
 fi