re PR driver/47390 (Linking with -export-dynamic broken)

	PR driver/47390
	* common.opt (export-dynamic): New Driver option.
	* gcc.c (LINK_COMMAND_SPEC): Add comment about %{e*}.

From-SVN: r170253

gcc/ChangeLog

 2011-02-17  Joseph Myers  <joseph@codesourcery.com>
 
+	PR driver/47390
+	* common.opt (export-dynamic): New Driver option.
+	* gcc.c (LINK_COMMAND_SPEC): Add comment about %{e*}.
+
+2011-02-17  Joseph Myers  <joseph@codesourcery.com>
+
 	* config/rx/rx.h (LIB_SPEC): Match -msim not -msim*.
 
 2011-02-17  Alexandre Oliva  <aoliva@redhat.com>

gcc/common.opt

@@ -712,6 +712,13 @@ Driver
 e
 Driver Joined Separate
 
+; This option has historically been passed down to the linker by an
+; accident of a %{e*} spec, so ensure it continues to be passed down
+; as a single option.  The supported option for this purpose is
+; -rdynamic.  See PR 47390.
+export-dynamic
+Driver Undocumented
+
 ; The version of the C++ ABI in use.  The following values are allowed:
 ;
 ; 0: The version of the ABI believed most conformant with the C++ ABI

gcc/gcc.c

@@ -644,6 +644,7 @@ proper position among the other output files.  */
    directories.  */
 /* We pass any -flto flags on to the linker, which is expected
    to understand them.  In practice, this means it had better be collect2.  */
+/* %{e*} includes -export-dynamic; see comment in common.opt.  */
 #ifndef LINK_COMMAND_SPEC
 #define LINK_COMMAND_SPEC "\
 %{!fsyntax-only:%{!c:%{!M:%{!MM:%{!E:%{!S:\