Use pkg_config to set the linker flags.

--- a/src/Makefile
+++ b/src/Makefile
@@ -1,7 +1,12 @@
 ifndef CFLAGS
 CFLAGS = -O2 -g -I ../src
 endif
-LIBS=-lnl -lnl-genl
+PKG_CONFIG ?= pkg-config
+PC_DEPS = libnl-3.0 libnl-genl-3.0
+PC_CFLAGS := $(shell $(PKG_CONFIG) --cflags $(PC_DEPS))
+PC_LIBS := $(shell $(PKG_CONFIG) --libs $(PC_DEPS))
+CFLAGS += $(PC_CFLAGS)
+LIBS += $(PC_LIBS)
 
 all: swconfig