Properly build against Qt 5 alpha.

Qt 5 alpha release has some build issues that should be addressed in order to build tp-qt against
it:
- When running configure in Qt 5 alpha, the pkgconfig files are properly generated, but when make is
executed, the files are replaced with empty ones, so to build tp-qt one must either backup the pkgconfig
files generated during the configure phase before running make and replace them afterwards,
or re-run configure with the same parameters after building it. (reported and should be fixed when
beta is out)
- If Qt 5 alpha is built with -reduce-relocations enabled, one must add the keyword
"reduce_relocations" to qtbase/lib/pkgconfig/QtCore.pc in the qt_config section, so that tp-qt knows
when to use -fPIC/PIE accordingly. (reported and should be fixed when beta is out)

1 files changed, 13 insertions, 1 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2b6bb854..b61c12f6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -83,6 +83,13 @@ set(QT5_MIN_VERSION "5.0.0")
 set(QT5_MAX_VERSION "6.0.0")
 find_package(Qt REQUIRED)
 
+foreach(flag ${QT_CONFIG_FLAGS})
+    if (${flag} MATCHES "reduce_relocations")
+        set(TP_QT_EXECUTABLE_LINKER_FLAGS "-fPIE")
+        set(TP_QT_LIBRARY_LINKER_FLAGS "-fPIC")
+    endif (${flag} MATCHES "reduce_relocations")
+endforeach(flag ${QT_CONFIG_FLAGS})
+
 # This value contains the library's SOVERSION. This value is to be increased everytime an API/ABI break
 # occurs, and will be used for the SOVERSION of the generated shared libraries.
 if (${QT_VERSION_MAJOR} EQUAL 4)
@@ -124,7 +131,9 @@ endif (ENABLE_DEBUG_OUTPUT)
 include(CheckCXXSourceCompiles)
 set(CMAKE_REQUIRED_INCLUDES ${QT_INCLUDES})
 set(CMAKE_REQUIRED_DEFINITIONS "")
-set(CMAKE_REQUIRED_FLAGS "")
+# set the flags (-fPIE) here so that CHECK_CXX_SOURCE_COMPILES works properly if qt5 was built with
+# -reduce-locations
+set(CMAKE_REQUIRED_FLAGS "${TP_QT_EXECUTABLE_LINKER_FLAGS}")
 
 CHECK_CXX_SOURCE_COMPILES("
 #include <QtCore/QtGlobal>
@@ -141,6 +150,9 @@ macro_log_feature(QT_GLIB_SUPPORT "Qt Glib Support"
                   "http://qt.nokia.com/" FALSE ""
                   "Needed, together with Telepathy-Glib, to build most of the unit tests")
 
+# reset flags
+set(CMAKE_REQUIRED_FLAGS "")
+
 # Find python version >= 2.5
 find_package(PythonLibrary REQUIRED)
 set(REQUIRED_PY 2.5)