Debian build: Include buildflags

Include the buildflags without patching upstream source. We just
need to export the variables correctly for this to work.

debian/patches/002-add-fortify-flags.patch

@@ -1,15 +0,0 @@
-Description: Add the FORTIFY_SOURCE build flag
-Author: Alan M Varghese <alan@digistorm.in>
-Last-Update: 2024-03-09
-Forwarded: not-needed
---- a/CMakeLists.txt
-+++ b/CMakeLists.txt
-@@ -37,7 +37,7 @@
- 
- include_directories(.)
- add_compile_options(-std=c++2b -DWLR_USE_UNSTABLE )
--add_compile_options(-Wall -Wextra -Wno-unused-parameter -Wno-unused-value -Wno-missing-field-initializers -Wno-narrowing)
-+add_compile_options(-Wall -Wextra -Wno-unused-parameter -Wno-unused-value -Wno-missing-field-initializers -Wno-narrowing -D_FORTIFY_SOURCE=2)
- find_package(Threads REQUIRED)
- 
- find_package(PkgConfig REQUIRED)

debian/patches/series

@@ -1,2 +1 @@
 001-create-directories-in-install-path.patch
-002-add-fortify-flags.patch

debian/rules

@@ -4,6 +4,9 @@ export DEB_BUILD_MAINT_OPTIONS = hardening=+all
 export DEB_CFLAGS_MAINT_APPEND  = -Wall -pedantic
 export DEB_LDFLAGS_MAINT_APPEND = -Wl,-O1
 
+export CPPFLAGS:=$(shell dpkg-buildflags --get CPPFLAGS)
+export CXXFLAGS:=$(shell dpkg-buildflags --get CXXFLAGS) $(CPPFLAGS)
+
 %:
 	dh $@