build: Use fPIC rather than fPIE for qt objects.

But only if qt was built with reduced relocations.

build-aux/m4/bitcoin_qt.m4

@@ -160,6 +160,43 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
     fi
   fi
 
+  if test x$use_hardening != xno; then
+    BITCOIN_QT_CHECK([
+    AC_MSG_CHECKING(whether -fPIE can be used with this Qt config)
+    TEMP_CPPFLAGS=$CPPFLAGS
+    TEMP_CXXFLAGS=$CXXFLAGS
+    CPPFLAGS="$QT_INCLUDES $CPPFLAGS"
+    CXXFLAGS="$PIE_FLAGS $CXXFLAGS"
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <QtCore/qconfig.h>]],
+      [[
+          #if defined(QT_REDUCE_RELOCATIONS)
+              choke;
+          #endif
+      ]])],
+      [ AC_MSG_RESULT(yes); QT_PIE_FLAGS=$PIE_FLAGS ],
+      [ AC_MSG_RESULT(no); QT_PIE_FLAGS=$PIC_FLAGS]
+    )
+    CPPFLAGS=$TEMP_CPPFLAGS
+    CXXFLAGS=$TEMP_CXXFLAGS
+    ])
+  else
+    BITCOIN_QT_CHECK([
+    AC_MSG_CHECKING(whether -fPIC is needed with this Qt config)
+    TEMP_CPPFLAGS=$CPPFLAGS
+    CPPFLAGS="$QT_INCLUDES $CPPFLAGS"
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <QtCore/qconfig.h>]],
+      [[
+          #if defined(QT_REDUCE_RELOCATIONS)
+              choke;
+          #endif
+      ]])],
+      [ AC_MSG_RESULT(no)],
+      [ AC_MSG_RESULT(yes); QT_PIE_FLAGS=$PIC_FLAGS]
+    )
+    CPPFLAGS=$TEMP_CPPFLAGS
+    ])
+  fi
+
   BITCOIN_QT_PATH_PROGS([MOC], [moc-qt${bitcoin_qt_got_major_vers} moc${bitcoin_qt_got_major_vers} moc], $qt_bin_path)
   BITCOIN_QT_PATH_PROGS([UIC], [uic-qt${bitcoin_qt_got_major_vers} uic${bitcoin_qt_got_major_vers} uic], $qt_bin_path)
   BITCOIN_QT_PATH_PROGS([RCC], [rcc-qt${bitcoin_qt_got_major_vers} rcc${bitcoin_qt_got_major_vers} rcc], $qt_bin_path)
@@ -205,6 +242,7 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
   ])
   AC_MSG_RESULT([$bitcoin_enable_qt (Qt${bitcoin_qt_got_major_vers})])
 
+  AC_SUBST(QT_PIE_FLAGS)
   AC_SUBST(QT_INCLUDES)
   AC_SUBST(QT_LIBS)
   AC_SUBST(QT_LDFLAGS)

src/Makefile.qt.include

@@ -329,7 +329,7 @@ BITCOIN_QT_INCLUDES = -I$(builddir)/qt -I$(srcdir)/qt -I$(srcdir)/qt/forms \
 
 qt_libbitcoinqt_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(BITCOIN_QT_INCLUDES) \
   $(QT_INCLUDES) $(QT_DBUS_INCLUDES) $(PROTOBUF_CFLAGS) $(QR_CFLAGS)
-qt_libbitcoinqt_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
+qt_libbitcoinqt_a_CXXFLAGS = $(AM_CXXFLAGS) $(QT_PIE_FLAGS)
 
 qt_libbitcoinqt_a_SOURCES = $(BITCOIN_QT_CPP) $(BITCOIN_QT_H) $(QT_FORMS_UI) \
   $(QT_QRC) $(QT_QRC_LOCALE) $(QT_TS) $(PROTOBUF_PROTO) $(RES_ICONS) $(RES_IMAGES) $(RES_MOVIES)
@@ -353,7 +353,7 @@ $(QT_MOC_CPP): $(PROTOBUF_H)
 # bitcoin-qt binary #
 qt_bitcoin_qt_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(BITCOIN_QT_INCLUDES) \
   $(QT_INCLUDES) $(PROTOBUF_CFLAGS) $(QR_CFLAGS)
-qt_bitcoin_qt_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
+qt_bitcoin_qt_CXXFLAGS = $(AM_CXXFLAGS) $(QT_PIE_FLAGS)
 
 qt_bitcoin_qt_SOURCES = qt/bitcoin.cpp
 if TARGET_DARWIN

src/Makefile.qttest.include

@@ -38,7 +38,7 @@ qt_test_test_bitcoin_qt_LDADD += $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBIT
   $(QR_LIBS) $(PROTOBUF_LIBS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS) $(LIBSECP256K1) \
   $(EVENT_PTHREADS_LIBS) $(EVENT_LIBS)
 qt_test_test_bitcoin_qt_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(QT_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
-qt_test_test_bitcoin_qt_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
+qt_test_test_bitcoin_qt_CXXFLAGS = $(AM_CXXFLAGS) $(QT_PIE_FLAGS)
 
 CLEAN_BITCOIN_QT_TEST = $(TEST_QT_MOC_CPP) qt/test/*.gcda qt/test/*.gcno