diff --git a/math/csdp/files/patch-Makefile b/math/csdp/files/patch-Makefile
index edb5223924a4..6bff733238d2 100644
--- a/math/csdp/files/patch-Makefile
+++ b/math/csdp/files/patch-Makefile
@@ -1,33 +1,35 @@
+- replacement of -ansi with -std=c99 is to work around https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=260136
+
 --- Makefile.orig	2017-07-25 18:44:57 UTC
 +++ Makefile
 @@ -11,11 +11,11 @@
  #
  # CFLAGS settings for 64 bit Linux/unix systems.
  #
 -export CFLAGS=-m64 -march=native -mtune=native -Ofast -fopenmp -ansi -Wall -DBIT64 -DUSEOPENMP -DSETNUMTHREADS -DUSESIGTERM -DUSEGETTIME -I../include
-+CFLAGS=$(FREEBSD_CFLAGS) -fopenmp -ansi -Wall -DBIT64 -DUSEOPENMP -DSETNUMTHREADS -DUSESIGTERM -DUSEGETTIME -I../include
++CFLAGS=$(FREEBSD_CFLAGS) -fopenmp -std=c99 -Wall -DBIT64 -DUSEOPENMP -DSETNUMTHREADS -DUSESIGTERM -DUSEGETTIME -I../include
  #
  # LIBS settings for 64 bit Linux/unix systems.
  #
 -export LIBS=-static -L../lib -lsdp -llapack -lblas -lm
 +LIBS=$(FREEBSD_LIBS) -L../lib -lsdp -llapack -lblas -lm
  #
  #
  # On most systems, this should handle everything.
 @@ -38,11 +38,11 @@ unitTest:
  #
  
  install:
 -	cp -f solver/csdp /usr/local/bin
 -	cp -f theta/theta /usr/local/bin
 -	cp -f theta/graphtoprob /usr/local/bin
 -	cp -f theta/complement /usr/local/bin
 -	cp -f theta/rand_graph /usr/local/bin
 +	cp -f solver/csdp $(DESTDIR)$(PREFIX)/bin
 +	cp -f theta/theta $(DESTDIR)$(PREFIX)/bin
 +	cp -f theta/graphtoprob $(DESTDIR)$(PREFIX)/bin
 +	cp -f theta/complement $(DESTDIR)$(PREFIX)/bin
 +	cp -f theta/rand_graph $(DESTDIR)$(PREFIX)/bin
  
  #
  # Clean out all of the directories.