title: Compilation problems with ZLIB
body: <p>I would like to compile some third-party software but I encounter a problem with ZLIB apparently. </p>
  
  <p>See below:</p>
  
  <pre><code> $sudo make
      gcc -Wall -pedantic -DVERSION=1.2 -lz -O3 sliding.o trim_single.o trim_paired.o sickle.o -o sickle
      trim_paired.o: In function `ks_getuntil':
      trim_paired.c:(.text+0x78): undefined reference to `gzread'
      trim_paired.o: In function `kseq_read':
      trim_paired.c:(.text+0x48d): undefined reference to `gzread'
      trim_paired.c:(.text+0x4dc): undefined reference to `gzread'
      trim_paired.c:(.text+0x60a): undefined reference to `gzread'
      trim_paired.c:(.text+0x687): undefined reference to `gzread'
      trim_paired.o: In function `paired_main':
      trim_paired.c:(.text+0xc62): undefined reference to `gzopen'
      trim_paired.c:(.text+0xc83): undefined reference to `gzopen'
      trim_paired.c:(.text+0x1142): undefined reference to `gzclose'
      trim_paired.c:(.text+0x114f): undefined reference to `gzclose'
      trim_single.o: In function `ks_getuntil':
      trim_single.c:(.text+0x78): undefined reference to `gzread'
      trim_single.o: In function `single_main':
      trim_single.c:(.text+0x688): undefined reference to `gzopen'
      trim_single.c:(.text+0x8ad): undefined reference to `gzread'
      trim_single.c:(.text+0x8f5): undefined reference to `gzread'
      trim_single.c:(.text+0xb11): undefined reference to `gzread'
      trim_single.c:(.text+0xb96): undefined reference to `gzread'
      trim_single.c:(.text+0xc58): undefined reference to `gzclose'
      collect2: ld returned 1 exit status
      make: *** [build] Error 1
  </code></pre>
  
  <p>I am using Ubuntu and I did install ZLIB 1.2.6 in /usr/local/lib </p>
  
  <p>Here is the Makefile:</p>
  
  <pre><code>PROGRAM_NAME = sickle
  VERSION = 1.2
  CC = gcc
  CFLAGS = -Wall -pedantic -DVERSION=$(VERSION)
  DEBUG = -g
  OPT = -O3
  ARCHIVE = $(PROGRAM_NAME)_$(VERSION)
  LDFLAGS = -lz
  SDIR = src
  
  .PHONY: clean default build distclean dist debug
  
  default: build
  
  sliding.o: $(SDIR)/sliding.c $(SDIR)/kseq.h $(SDIR)/sickle.h
      $(CC) $(CFLAGS) $(OPT) -c $(SDIR)/$*.c
  
  trim_single.o: $(SDIR)/trim_single.c $(SDIR)/sickle.h $(SDIR)/kseq.h
      $(CC) $(CFLAGS) $(OPT) -c $(SDIR)/$*.c
  
  trim_paired.o: $(SDIR)/trim_paired.c $(SDIR)/sickle.h $(SDIR)/kseq.h
      $(CC) $(CFLAGS) $(OPT) -c $(SDIR)/$*.c
  
  sickle.o: $(SDIR)/sickle.c $(SDIR)/sickle.h
      $(CC) $(CFLAGS) $(OPT) -c $(SDIR)/$*.c
  
  clean:
      rm -rf *.o $(SDIR)/*.gch ./sickle
  
  distclean: clean
      rm -rf *.tar.gz
  
  dist:
      tar -zcf $(ARCHIVE).tar.gz src Makefile
  
  build: sliding.o trim_single.o trim_paired.o sickle.o
      $(CC) $(CFLAGS) $(LDFLAGS) $(OPT) $? -o sickle
  
  debug:
      $(MAKE) build "CFLAGS=-Wall -pedantic -g -DDEBUG"
  </code></pre>
  
  <p>Any help is appreciated ;)</p>
  
  <p>Thanks</p>