see https://bitbucket.org/breakfastquay/rubberband/issues/23/macos-system-test-in-src-system-vectoropsh
--- src/system/VectorOps.h.orig	2018-05-27 14:05:45.000000000 -0700
+++ src/system/VectorOps.h	2018-05-27 14:07:44.000000000 -0700
@@ -677,7 +677,7 @@
                   const int count)
 {
     float tmp[count];
-#if (defined(MACOSX_DEPLOYMENT_TARGET) && MACOSX_DEPLOYMENT_TARGET <= 1070 && MAC_OS_X_VERSION_MIN_REQUIRED <= 1070)
+#if (defined(MAC_OS_X_VERSION_MIN_REQUIRED) && MAC_OS_X_VERSION_MIN_REQUIRED < 1070)
     vvfabf(tmp, dst, &count);
 #else
     vvfabsf(tmp, dst, &count);