Build MMX/SSE FFT only if CONFIG_FFT is set

Originally committed as revision 15692 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -858,6 +858,11 @@ HAVE_LIST="
     yasm
 "
 
+# options emitted with CONFIG_ prefix but not available on command line
+CONFIG_EXTRA="
+    fft_mmx
+"
+
 CMDLINE_SELECT="
     $ARCH_EXT_LIST
     $CONFIG_LIST
@@ -909,6 +914,10 @@ neon_deps="armv4l"
 ssse3_deps="x86"
 vis_deps="sparc"
 
+# common features
+fft_suggest="fft_mmx"
+fft_mmx_deps="mmx yasm"
+
 # decoders / encoders
 aac_decoder_select="fft"
 ac3_decoder_deps="gpl"
@@ -2015,6 +2024,7 @@ enabled_any $PROTOCOL_LIST     && enable protocols
 enabled_any $THREADS_LIST      && enable threads
 
 check_deps $CONFIG_LIST       \
+           $CONFIG_EXTRA      \
            $HAVE_LIST         \
            $DECODER_LIST      \
            $ENCODER_LIST      \
@@ -2224,6 +2234,7 @@ echo "EXTRALIBS=$extralibs" >> config.mak
 print_config ARCH_   $TMPH config.mak $ARCH_LIST
 print_config HAVE_   $TMPH config.mak $HAVE_LIST
 print_config CONFIG_ $TMPH config.mak $CONFIG_LIST       \
+                                      $CONFIG_EXTRA      \
                                       $DECODER_LIST      \
                                       $ENCODER_LIST      \
                                       $PARSER_LIST       \

libavcodec/Makefile

@@ -395,11 +395,12 @@ OBJS += i386/fdct_mmx.o \
         i386/idct_mmx_xvid.o \
         i386/idct_sse2_xvid.o \
 
-OBJS-$(HAVE_YASM)                      += i386/fft_mmx.o \
+OBJS-$(CONFIG_FFT_MMX)                 += i386/fft_mmx.o \
                                           i386/fft_sse.o \
                                           i386/fft_3dn.o \
                                           i386/fft_3dn2.o \
-                                          i386/dsputil_yasm.o \
+
+OBJS-$(HAVE_YASM)                      += i386/dsputil_yasm.o
 
 OBJS-$(CONFIG_GPL)                     += i386/idct_mmx.o