Only require librtlsdr headers while we're compiling dump1090,

not the other helpers that don't use the dongle.

Makefile

@@ -15,7 +15,7 @@ EXTRACFLAGS=-DHTMLPATH=\"$(SHAREDIR)\"
 endif
 
 CPPFLAGS+=-DMODES_DUMP1090_VERSION=\"$(DUMP1090_VERSION)\"
-CFLAGS+=-O2 -g -Wall -Werror -W `pkg-config --cflags librtlsdr`
+CFLAGS+=-O2 -g -Wall -Werror -W
 LIBS=-lpthread -lm -lrt
 LIBS_RTL=`pkg-config --libs librtlsdr`
 CC=gcc
@@ -25,6 +25,8 @@ all: dump1090 view1090
 %.o: %.c *.h
 	$(CC) $(CPPFLAGS) $(CFLAGS) $(EXTRACFLAGS) -c $< -o $@
 
+dump1090.o: CFLAGS += `pkg-config --cflags librtlsdr`
+
 dump1090: dump1090.o anet.o interactive.o mode_ac.o mode_s.o net_io.o crc.o demod_2000.o demod_2400.o stats.o cpr.o icao_filter.o track.o util.o convert.o
 	$(CC) -g -o $@ $^ $(LIBS) $(LIBS_RTL) $(LDFLAGS)
 

dump1090.c

@@ -49,6 +49,8 @@
 
 #include "dump1090.h"
 
+#include <rtl-sdr.h>
+
 #include <stdarg.h>
 #include <endian.h>