Merge.

js/src/configure.in

@@ -2478,35 +2478,38 @@ fi
 
 dnl Configure SSE2 support
 
-HAVE_SSE2=
-MUST_DETECT_SSE2=
+dnl Enable SSE2 support in the compiler if available.
+dnl ========================================================
 case "$target" in
-i?86-*)
-    HAVE_SSE2=1
-    case "$target_os" in
-    darwin*)
-        ;;
-    *)
-        MUST_DETECT_SSE2=1
-        ;;
-    esac
-    ;;
-x86_64*-*)e
-    HAVE_SSE2=1
-    ;;
-esac
-
-if test "$HAVE_SSE2"; then
-    AC_DEFINE(HAVE_SSE2)
+i?86-*|x86_64*-*)
     if test "$GNU_CC"; then
         CFLAGS="$CFLAGS -msse2"
     fi
     if test "$GNU_CXX"; then
         CXXFLAGS="$CXXFLAGS -msse2"
     fi
-    if test "$MUST_DETECT_SSE2"; then
-        AC_DEFINE(MUST_DETECT_SSE2)
-    fi
+    ;;
+esac
+
+dnl If we have the proper include file, enable SSE2 support.
+dnl ========================================================
+HAVE_SSE2=
+AC_CHECK_HEADER(xmmintrin.h, HAVE_SSE2=1)
+AC_CHECK_HEADER(emmintrin.h, HAVE_SSE2=1 && AC_DEFINE(USE_EMM_INTRIN))
+
+if test "$HAVE_SSE2"; then
+    AC_DEFINE(HAVE_SSE2)
+    case "$target_os" in
+    darwin*)
+        ;;
+    *)
+        case "$target" in
+        i?86-*)
+            AC_DEFINE(MUST_DETECT_SSE2)
+            ;;
+        esac
+        ;;
+    esac
 fi
 
 dnl Configure JIT support

js/src/jsnum.h

@@ -48,10 +48,10 @@
 #include <ieeefp.h>
 #endif
 #ifdef HAVE_SSE2
-#ifdef __GNUC__
-#include <xmmintrin.h>
-#else
+#ifdef USE_EMM_INTRIN
 #include <emmintrin.h>
+#else
+#include <xmmintrin.h>
 #endif
 #endif