diff -ru rtmidi-3.0.0/configure.ac rtmidi-3.0.0-fixed/configure.ac
--- rtmidi-3.0.0/configure.ac	2017-09-01 00:10:07.000000000 +0000
+++ rtmidi-3.0.0-fixed/configure.ac	2017-11-01 18:03:27.802660669 +0000
@@ -85,7 +85,7 @@
 
 # For debugging and optimization ... overwrite default because it has both -g and -O2
 #CXXFLAGS="$CXXFLAGS $cxxflag"
-CXXFLAGS="$cxxflag"
+# CXXFLAGS="$cxxflag"
 
 # Check compiler and use -Wall if gnu.
 if [test $GXX = "yes" ;] then