Add openssl/aes.h in Qt project - qt

Question

I have a custom library I've called libdblib.a that I'm using on several projects, and this time I would like to use it in a Qt Project.
So I've added this library as an external library through Qt Creator, so far so good.
Thing is, my library needs openSSl support (especially aes functions), and I don't understand how to add it in the project.
I've already checked this website : http://doc.qt.io/qt-5/opensslsupport.html but it seems to concern Android stuff, so I don't feel it will help
Obviously, I have the necessary ssl libraries on my computer, I'm just trying to understand how to add it in my Qt Project.
Sorry if it's an "easy question", but I'm still figuring out Qt mechanics.
I'm here if you have more questions, so far my .pro looks like this :
QT += core gui network printsupport \
sql
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
#qtHaveModule(printsupport): QT += printsupport
TARGET = myTarget
TEMPLATE = app
CONFIG += warn_off
SOURCES += \
/* list of my sources */
HEADERS += \
/* list of my headers */
/* I'm guessing I have to add something here to make ssl work... */
LIBS += -lsqlite3 \
-L/usr/local/lib \
-lxml2
CONFIG += c++11
/* the following has been added by Qt creator when I imported my external lib */
win32:CONFIG(release, debug|release): LIBS += -L$$PWD/Utils/release/ -ldblib
else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/Utils/debug/ -ldblib
else:unix: LIBS += -L$$PWD/Utils/ -ldblib
INCLUDEPATH += $$PWD/Utils
DEPENDPATH += $$PWD/Utils
win32-g++:CONFIG(release, debug|release): PRE_TARGETDEPS += $$PWD/Utils/release/libdblib.a
else:win32-g++:CONFIG(debug, debug|release): PRE_TARGETDEPS += $$PWD/Utils/debug/libdblib.a
else:win32:!win32-g++:CONFIG(release, debug|release): PRE_TARGETDEPS += $$PWD/Utils/release/dblib.lib
else:win32:!win32-g++:CONFIG(debug, debug|release): PRE_TARGETDEPS += $$PWD/Utils/debug/dblib.lib
else:unix: PRE_TARGETDEPS += $$PWD/Utils/libdblib.a