Patch Makefile to use existing installation of libquirc
--- ./Makefile
+++ ./Makefile
@@ -17,12 +17,7 @@ endif
 CC ?= gcc
 PREFIX ?= /usr/local
 
-QUIRC = quirc/lib
 OBJS = \
-	$(QUIRC)/decode.o \
-	$(QUIRC)/identify.o \
-	$(QUIRC)/quirc.o \
-	$(QUIRC)/version_db.o \
 	src/main.o \
 	src/options.o \
 	src/qrcode.o \
@@ -31,8 +26,8 @@ OBJS = \
 	src/jpg_reader.o
 TARGET = qrscan
 
-CFLAGS += -I$(QUIRC) $(shell $(PKG_CONFIG) --cflags --static libpng libjpeg)
-LDFLAGS += -lz -lm
+CFLAGS += -std=c99 $(shell $(PKG_CONFIG) --cflags --static libpng libjpeg)
+LDFLAGS += -lz -lm -lquirc
 ifeq ($(shell uname -s),Darwin)
 	GROUP = staff
   LDFLAGS += $(shell $(PKG_CONFIG) --variable=libdir --static libpng)/libpng.a