[2667] Add --disable-rpath configure switch.

Some dynamic linkers are wise enough (at least the Linux one) to correctly pick
needed shared libraries without hardcoded rpath. The --disable-rpath configure
switch allows distributors to avoid hardcoded rpath paths in libraries and
executables.

Signed-off-by: Adam Tkac <atkac@redhat.com>

examples/m4/ax_isc_rpath.m4

@@ -9,38 +9,46 @@ dnl the found option flag.  The main configure.ac can use it as follows:
 dnl if test "x$ISC_RPATH_FLAG" != "x"; then
 dnl     LDFLAGS="$LDFLAGS ${ISC_RPATH_FLAG}/usr/local/lib/some_library"
 dnl fi
+dnl
+dnl If you pass --disable-rpath to configure, ISC_RPATH_FLAG is not set
 
 AC_DEFUN([AX_ISC_RPATH], [
 
-# We'll tweak both CXXFLAGS and CCFLAGS so this function will work whichever
-# language is used in the main script.  Note also that it's not LDFLAGS;
-# technically this is a linker flag, but we've noticed $LDFLAGS can be placed
-# where the compiler could interpret it as a compiler option, leading to
-# subtle failure mode.  So, in the check below using the compiler flag is
-# safer (in the actual Makefiles the flag should be set in LDFLAGS).
-CXXFLAGS_SAVED="$CXXFLAGS"
-CXXFLAGS="$CXXFLAGS -Wl,-R/usr/lib"
-CCFLAGS_SAVED="$CCFLAGS"
-CCFLAGS="$CCFLAGS -Wl,-R/usr/lib"
+AC_ARG_ENABLE(rpath,
+    [AC_HELP_STRING([--disable-rpath], [don't hardcode library path into binaries])],
+    rpath=$enableval, rpath=yes)
+
+if test x$rpath != xno; then
+    # We'll tweak both CXXFLAGS and CCFLAGS so this function will work whichever
+    # language is used in the main script.  Note also that it's not LDFLAGS;
+    # technically this is a linker flag, but we've noticed $LDFLAGS can be placed
+    # where the compiler could interpret it as a compiler option, leading to
+    # subtle failure mode.  So, in the check below using the compiler flag is
+    # safer (in the actual Makefiles the flag should be set in LDFLAGS).
+    CXXFLAGS_SAVED="$CXXFLAGS"
+    CXXFLAGS="$CXXFLAGS -Wl,-R/usr/lib"
+    CCFLAGS_SAVED="$CCFLAGS"
+    CCFLAGS="$CCFLAGS -Wl,-R/usr/lib"
 
-# check -Wl,-R and -R rather than gcc specific -rpath to be as portable
-# as possible.  -Wl,-R seems to be safer, so we try it first.  In some cases
-# -R is not actually recognized but AC_TRY_LINK doesn't fail due to that.
-AC_MSG_CHECKING([whether -Wl,-R flag is available in linker])
-AC_TRY_LINK([],[],
-    [ AC_MSG_RESULT(yes)
-        ISC_RPATH_FLAG=-Wl,-R
-    ],[ AC_MSG_RESULT(no)
-        AC_MSG_CHECKING([whether -R flag is available in linker])
-	CXXFLAGS="$CXXFLAGS_SAVED -R"
-	CCFLAGS="$CCFLAGS_SAVED -R"
+    # check -Wl,-R and -R rather than gcc specific -rpath to be as portable
+    # as possible.  -Wl,-R seems to be safer, so we try it first.  In some cases
+    # -R is not actually recognized but AC_TRY_LINK doesn't fail due to that.
+    AC_MSG_CHECKING([whether -Wl,-R flag is available in linker])
+    AC_TRY_LINK([],[],
+        [ AC_MSG_RESULT(yes)
+            ISC_RPATH_FLAG=-Wl,-R
+        ],[ AC_MSG_RESULT(no)
+            AC_MSG_CHECKING([whether -R flag is available in linker])
+            CXXFLAGS="$CXXFLAGS_SAVED -R"
+            CCFLAGS="$CCFLAGS_SAVED -R"
         AC_TRY_LINK([], [],
             [ AC_MSG_RESULT([yes; note that -R is more sensitive about the position in option arguments])
                 ISC_RPATH_FLAG=-R
             ],[ AC_MSG_RESULT(no) ])
-    ])
+        ])
 
-CXXFLAGS=$CXXFLAGS_SAVED
-CCFLAGS=$CCFLAGS_SAVED
+    CXXFLAGS=$CXXFLAGS_SAVED
+    CCFLAGS=$CCFLAGS_SAVED
+fi
 
 ])dnl AX_ISC_RPATH