Respect the compiler and flags supplied by the package manager.

--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,8 @@
-CC = gcc
+CC ?= gcc
+CFLAGS += -fPIC
+LDFLAGS += -shared
 INCLUDES = $(shell pkg-config --cflags gio-2.0 glib-2.0)
 LIBS = $(shell pkg-config --libs gio-2.0 glib-2.0)
-OPTIONS = -fPIC -shared
 NAME = ddb_gnome_mmkeys
 ROOTDIR = /
 INSTALL_DIR = usr/lib/deadbeef
@@ -12,6 +13,6 @@ plugin: $(NAME).so
 
 $(NAME).so: $(NAME).c
-	$(CC) $(INCLUDES) $(OPTIONS) -o $(NAME).so $(NAME).c $(LIBS)
+	$(CC) $(INCLUDES) $(CFLAGS) $(LDFLAGS) -o $(NAME).so $(NAME).c $(LIBS)
 
 install:
 	mkdir -p $(ROOTDIR)$(INSTALL_DIR)