bug 563751 - add configure option to enable building for thumb2 instruction set r=ted

configure.in

@@ -5014,6 +5014,7 @@ MOZ_SPELLCHECK=1
 MOZ_SPLASHSCREEN=
 MOZ_STORAGE=1
 MOZ_SVG=1
+MOZ_THUMB2=
 MOZ_TIMELINE=
 MOZ_TOOLKIT_SEARCH=1
 MOZ_UI_LOCALE=en-US
@@ -6845,6 +6846,10 @@ if test $MOZ_PLATFORM_MAEMO; then
 
    fi
 
+   if test "$MOZ_PLATFORM_MAEMO" -gt 5; then
+     MOZ_THUMB2=1
+   fi
+
    PKG_CHECK_MODULES(LIBLOCATION,liblocation, _LIB_FOUND=1, _LIB_FOUND=)
    MOZ_PLATFORM_MAEMO_LIBS="$MOZ_PLATFORM_MAEMO_LIBS $LIBLOCATION_LIBS"
    MOZ_PLATFORM_MAEMO_CFLAGS="$MOZ_PLATFORM_MAEMO_CFLAGS $LIBLOCATION_CFLAGS"
@@ -6860,6 +6865,31 @@ if test $MOZ_PLATFORM_MAEMO; then
    AC_SUBST(MOZ_PLATFORM_MAEMO_CFLAGS)
 fi
 
+dnl ========================================================
+dnl = Enable building the Thumb2 instruction set
+dnl ========================================================
+MOZ_ARG_ENABLE_BOOL(thumb2,
+ [  --enable-thumb2              Enable Thumb2 instruction set],
+    MOZ_THUMB2=1,
+    MOZ_THUMB2=)
+
+if test -n "$MOZ_THUMB2"; then
+  case "$target_cpu" in
+    arm*)
+      if test "$GNU_CC"; then
+        CFLAGS="$CFLAGS -march=armv7-a -mthumb -Wa, -march=armv7-a -Wa, -mthumb"
+        CXXFLAGS="$CXXFLAGS -march=armv7-a -mthumb -Wa, -march=armv7-a -Wa, -mthumb"
+        ASFLAGS="$ASFLAGS -march=armv7-a -mthumb"
+      else
+        AC_MSG_ERROR([--enable-thumb2 is not supported for non-GNU toolchains])
+      fi
+    ;;
+    *)
+      AC_MSG_ERROR([--enable-thumb2 is not supported for non-ARM CPU architectures])
+    ;;
+  esac
+fi
+
 dnl ========================================================
 dnl = faststripe theme
 dnl ========================================================
@@ -8971,6 +9001,9 @@ if test -z "$MOZ_NATIVE_NSPR"; then
     if test -n "$USE_ARM_KUSER"; then
         ac_configure_args="$ac_configure_args --with-arm-kuser"
     fi
+    if test -n "$MOZ_THUMB2"; then
+        ac_configure_args="$ac_configure_args --enable-thumb2"
+    fi
     AC_OUTPUT_SUBDIRS(nsprpub)
     ac_configure_args="$_SUBDIR_CONFIG_ARGS"
 fi