Error linking TagLib to Qt

Question

If I try to reference the external TagLib library in my code (for example TagLib::FileRef f(path);), then when I build my Qt Creator project I get the following errors,

symbol(s) not found for architecture x86_64
linker command failed with exit code 1 (use -v to see invocation)

and

Undefined symbols for architecture x86_64:
  "_inflate", referenced from:
      TagLib::zlib::decompress(TagLib::ByteVector const&) in libtag.a(tzlib.cpp.o)
  "_inflateEnd", referenced from:
      TagLib::zlib::decompress(TagLib::ByteVector const&) in libtag.a(tzlib.cpp.o)
  "_inflateInit_", referenced from:
      TagLib::zlib::decompress(TagLib::ByteVector const&) in libtag.a(tzlib.cpp.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [Opus.app/Contents/MacOS/Opus] Error 1
21:06:29: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project Opus (kit: Desktop Qt 5.7.0 clang 64bit)
When executing step "Make"

My .pro file,

QT       += core gui sql

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = Opus
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp \
    tabunit.cpp \
    tabholder.cpp \
    dbmanager.cpp \
    articleadditiondialog.cpp \
    articlefilemodel.cpp \
    directoryiterator.cpp \
    articleattributes.cpp

HEADERS  += mainwindow.h \
    tabunit.h \
    tabholder.h \
    dbmanager.h \
    articleproperty.h \
    articleadditiondialog.h \
    articlefilemodel.h \
    directoryiterator.h \
    articleattributes.h

FORMS    += mainwindow.ui \
    articleadditiondialog.ui

LIBS += -L$$PWD/../../../Libraries/taglib-1.11.1/taglib/ -ltag

INCLUDEPATH += $$PWD/../../../Libraries/taglib-1.11.1/include

Under /Libraries/taglib-1.11.1/ I have this.

Any help would be appreciated, thanks.

Answer 1

Added

LIBS += -lz

to the .pro file