Remove Opus from DEPS and import a local copy

third_party/opus/src/m4/opus-intrinsics.m4

Index: third_party/opus/src/m4/opus-intrinsics.m4
diff --git a/third_party/opus/src/m4/opus-intrinsics.m4 b/third_party/opus/src/m4/opus-intrinsics.m4
new file mode 100644
index 0000000000000000000000000000000000000000..a262ca1818016247e75473a9448fe737dc331348
--- /dev/null
+++ b/third_party/opus/src/m4/opus-intrinsics.m4
@@ -0,0 +1,29 @@
+dnl opus-intrinsics.m4
+dnl macro for testing for support for compiler intrinsics, either by default or with a compiler flag
+
+dnl OPUS_CHECK_INTRINSICS(NAME-OF-INTRINSICS, COMPILER-FLAG-FOR-INTRINSICS, VAR-IF-PRESENT, VAR-IF-DEFAULT, TEST-PROGRAM-HEADER, TEST-PROGRAM-BODY)
+AC_DEFUN([OPUS_CHECK_INTRINSICS],
+[
+   AC_MSG_CHECKING([if compiler supports $1 intrinsics])
+   AC_LINK_IFELSE(
+     [AC_LANG_PROGRAM($5, $6)],
+     [
+        $3=1
+        $4=1
+        AC_MSG_RESULT([yes])
+      ],[
+        $4=0
+        AC_MSG_RESULT([no])
+        AC_MSG_CHECKING([if compiler supports $1 intrinsics with $2])
+        save_CFLAGS="$CFLAGS"; CFLAGS="$CFLAGS $2"
+        AC_LINK_IFELSE([AC_LANG_PROGRAM($5, $6)],
+        [
+           AC_MSG_RESULT([yes])
+           $3=1
+        ],[
+           AC_MSG_RESULT([no])
+           $3=0
+        ])
+        CFLAGS="$save_CFLAGS"
+     ])
+])