Subject: Remove redefinition of _FORTIFY_SOURCE
  Starting Ubuntu 24.04, dpkg-buildflags passes _FORTIFY_SOURCE=3 by default.
  On Debian, dpkg-buildflags passes _FORTIFY_SOURCE=2. Use of _FORTIFY_SOURCE=2
  in the Makefile causes redefinition errors on Ubuntu. This patch enforces
  depending on dpkg-buildflags for the _FORTIFY_SOURCE value.
Author: Pushkar Kulkarni <pushkar.kulkarni@canonical.com>
Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/linuxcnc/+bug/2104012


--- a/src/Makefile
+++ b/src/Makefile
@@ -252,7 +252,7 @@
 # Compilation options.	Perhaps some of these should come from Makefile.inc? (CXXFLAGS now does)
 INTEGER_OVERFLOW_FLAGS := -fwrapv
 OPT := -O2 $(INTEGER_OVERFLOW_FLAGS)
-DEBUG := $(DEBUG) -g -Wall -D_FORTIFY_SOURCE=2
+DEBUG := $(DEBUG) -g -Wall
 CFLAGS := $(INCLUDE) $(OPT) $(DEBUG) -DULAPI -std=gnu11 -Werror=implicit-function-declaration $(CFLAGS) $(CPPFLAGS) $(EXTRA_DEBUG)
 CXXFLAGS := $(INCLUDE) $(OPT) $(DEBUG) -DULAPI -Werror=overloaded-virtual $(CXXFLAGS) $(CPPFLAGS) $(EXTRA_DEBUG)
 # In Debian 11, any inclusion of <boost/python.hpp> leads to several