Index: trigger-rally/src/GNUmakefile
===================================================================
--- trigger-rally.orig/src/GNUmakefile	2019-02-06 19:04:22.000690970 +0100
+++ trigger-rally/src/GNUmakefile	2019-02-06 19:10:54.549511561 +0100
@@ -24,10 +24,10 @@
 OPTIMS          ?= -march=native -mtune=native -Ofast
 DMACROS         := -DNDEBUG -DUNIX -DPACKAGE_VERSION=\"$(DISTVER)\"
 INCDIRS         := -I'./include'
-CXXFLAGS        ?= -std=c++11 $(WARNINGS) $(OPTIMS)
-CPPFLAGS        ?= $(DMACROS) $(INCDIRS)
+CXXFLAGS        += -std=c++11 $(WARNINGS) $(OPTIMS)
+CPPFLAGS        += $(DMACROS) $(INCDIRS)
 EXTRA_LIBS      := -lSDL2main -lGL -lGLU -lGLEW -lSDL2 -lSDL2_image -lphysfs -lopenal -lalut -lpthread -ltinyxml2
-LDFLAGS         ?= $(EXTRA_LIBS)
+LDFLAGS         += $(EXTRA_LIBS)
 INSTALL_PROGRAM := install --mode=0755
 INSTALL_DATA    := install --mode=0644