Support hardened builds for nxcomp* libraries.

debian/changelog

@@ -46,6 +46,8 @@ nx-libs (2:3.5.0.29-0x2go2) UNRELEASED; urgency=medium
       no extra settings of LD_LIBRARY_PATH is necessary.
     + Add Multi-Arch support for Debian based distro versions that
       support Multi-Arch.
+    + Support hardened builds for nxcomp* libraries.
+
   * debian/rules:
     + Backup nxcomp/VERSION file from NoMachine before replacing it with
       a symlink to debian/VERSION. Recreate the original file when cleaning

debian/rules

 #!/usr/bin/make -f
 
 NULL =
-CFLAGS = -Wall -g
 
-ifneq (,$(findstring noopt,$(DEB_BUILD_OPTIONS)))
-        CFLAGS += -O0
-else
-        CFLAGS += -O2
-endif
+export CPPFLAGS:=$(shell dpkg-buildflags --get CPPFLAGS)
+export CFLAGS:=$(shell dpkg-buildflags --get CFLAGS)
+export CXXFLAGS:=$(shell dpkg-buildflags --get CXXFLAGS)
+export LDFLAGS:=$(shell dpkg-buildflags --get LDFLAGS)
 
 export LIBDIR = "/usr/lib/$(shell dpkg-architecture -qDEB_BUILD_MULTIARCH)"
 export INCLUDEDIR = "/usr/include/$(shell dpkg-architecture -qDEB_BUILD_MULTIARCH)"