rpath improvements

Improve on the previous commit adding QMAKE_RPATHDIR. We can now use
rpath for out-of-source builds, as well as on osx.

.travis.yml

@@ -11,5 +11,4 @@ script:
   - cd build
   - qmake ..
   - make
-  - export LD_LIBRARY_PATH=$PWD/src
   - make check

src/src.pro

@@ -9,6 +9,7 @@ DEFINES += QAMQP_BUILD
 CONFIG += $${QAMQP_LIBRARY_TYPE}
 VERSION = $${QAMQP_VERSION}
 win32:DESTDIR = $$OUT_PWD
+macx:QMAKE_LFLAGS_SONAME = -Wl,-install_name,@rpath/
 
 PRIVATE_HEADERS += \
     qamqpchannel_p.h \

tests/tests.pri

@@ -1,7 +1,11 @@
 INCLUDEPATH += $${QAMQP_INCLUDEPATH} $${PWD}/common
 LIBS += -L$${DEPTH}/src $${QAMQP_LIBS}
 
-QMAKE_RPATHDIR += $${DEPTH}/src
+unix:!macx:QMAKE_RPATHDIR += $${OUT_PWD}/$${DEPTH}/src
+macx {
+    QMAKE_RPATHDIR += @loader_path/$${DEPTH}/src
+    QMAKE_LFLAGS += -Wl,-rpath,@loader_path/$${DEPTH}/src
+}
 
 QT = core network testlib
 QT -= gui