rename --tune to --cpu and make --cpu pass the apropriate -march=xx option to the compiler.

Note that previous implementation (--tune) wasn't consistent with regards to setting -march/-mcpu/-mtune whereas current --cpu now is
Original thread:
Date: Oct 17, 2006 3:20 PM (patch) || Date: Oct 13, 2006 12:03 PM (suggestion of configure clean-up)
Subject: Re: [Ffmpeg-devel] [PATH] test if cpu supports CMOV

Originally committed as revision 6729 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -73,8 +73,8 @@ show_help(){
   echo "  --extra-libs=ELIBS       add ELIBS [$ELIBS]"
   echo "  --build-suffix=SUFFIX    suffix for application specific build []"
   echo "  --arch=ARCH              select architecture  [$arch]"
-  echo "  --tune=CPU               tune code for a particular CPU"
-  echo "                           (may fail or perform badly on other CPUs)"
+  echo "  --cpu=CPU                selects the minimum cpu required (affects
+                                   instruction selection, may crash on older CPUs)"
   echo "  --powerpc-perf-enable    enable performance report on PPC"
   echo "                           (requires enabling PMC)"
   echo "  --disable-mmx            disable MMX usage"
@@ -343,7 +343,7 @@ ranlib="ranlib"
 make="make"
 strip="strip"
 arch=`uname -m`
-tune="generic"
+cpu="generic"
 powerpc_perf="no"
 mmx="default"
 armv5te="default"
@@ -717,7 +717,7 @@ for opt do
   ;;
   --arch=*) arch="$optval"
   ;;
-  --tune=*) tune="$optval"
+  --cpu=*) cpu="$optval"
   ;;
   --powerpc-perf-enable) powerpc_perf="yes"
   ;;
@@ -1048,52 +1048,52 @@ fi
 # Add processor-specific flags
 TUNECPU="generic"
 POWERPCMODE="32bits"
-if test $tune != "generic"; then
-    case $tune in
+if test $cpu != "generic"; then
+    case $cpu in
         601|ppc601|PowerPC601)
-            add_cflags "-mcpu=601"
+            add_cflags "-march=601"
             if test $altivec = "yes"; then
                 echo "WARNING: Tuning for PPC601 but AltiVec enabled!";
             fi
             TUNECPU=ppc601
         ;;
         603*|ppc603*|PowerPC603*)
-            add_cflags "-mcpu=603"
+            add_cflags "-march=603"
             if test $altivec = "yes"; then
                 echo "WARNING: Tuning for PPC603 but AltiVec enabled!";
             fi
             TUNECPU=ppc603
         ;;
         604*|ppc604*|PowerPC604*)
-            add_cflags "-mcpu=604"
+            add_cflags "-march=604"
             if test $altivec = "yes"; then
                 echo "WARNING: Tuning for PPC604 but AltiVec enabled!";
             fi
             TUNECPU=ppc604
         ;;
         G3|g3|75*|ppc75*|PowerPC75*)
-            add_cflags "-mcpu=750 -mtune=750 -mpowerpc-gfxopt"
+            add_cflags "-march=750 -mpowerpc-gfxopt"
             if test $altivec = "yes"; then
                 echo "WARNING: Tuning for PPC75x but AltiVec enabled!";
             fi
             TUNECPU=ppc750
         ;;
         G4|g4|745*|ppc745*|PowerPC745*)
-            add_cflags "-mcpu=7450 -mtune=7450 -mpowerpc-gfxopt"
+            add_cflags "-march=7450 -mpowerpc-gfxopt"
             if test $altivec = "no"; then
                 echo "WARNING: Tuning for PPC745x but AltiVec disabled!";
             fi
             TUNECPU=ppc7450
         ;;
         74*|ppc74*|PowerPC74*)
-            add_cflags "-mcpu=7400 -mtune=7400 -mpowerpc-gfxopt"
+            add_cflags "-march=7400 -mpowerpc-gfxopt"
             if test $altivec = "no"; then
                 echo "WARNING: Tuning for PPC74xx but AltiVec disabled!";
             fi
             TUNECPU=ppc7400
         ;;
         G5|g5|970|ppc970|PowerPC970|power4*|Power4*)
-            add_cflags "-mcpu=970 -mtune=970 -mpowerpc-gfxopt -mpowerpc64"
+            add_cflags "-march=970 -mpowerpc-gfxopt -mpowerpc64"
             if test $altivec = "no"; then
                 echo "WARNING: Tuning for PPC970 but AltiVec disabled!";
             fi
@@ -1101,13 +1101,13 @@ if test $tune != "generic"; then
             POWERPCMODE="64bits"
         ;;
         i[3456]86|pentium|pentiumpro|pentium-mmx|pentium[234]|pentium-m|prescott|k6|k6-[23]|athlon|athlon-tbird|athlon-4|athlon-[mx]p|winchip-c6|winchip2|c3|nocona|athlon64|k8|opteron|athlon-fx)
-            add_cflags "-march=$tune"
+            add_cflags "-march=$cpu"
         ;;
         sparc64)
-            add_cflags "-mcpu=v9 -mtune=v9"
+            add_cflags "-march=v9"
         ;;
         *)
-        echo "WARNING: Unknown CPU \"$tune\", ignored."
+        echo "WARNING: Unknown CPU \"$cpu\", ignored."
         ;;
     esac
 fi
@@ -1541,7 +1541,7 @@ echo "install prefix   $PREFIX"
 echo "source path      $source_path"
 echo "C compiler       $cc"
 echo "make             $make"
-echo "ARCH             $arch ($tune)"
+echo "ARCH             $arch ($cpu)"
 if test "$BUILDSUF" != ""; then
     echo "build suffix     $BUILDSUF"
 fi