Tested x86_64-linux, without libiconv installed, with libiconv installed,
with libiconv installed but using an in-tree libiconv, with libiconv.a
installed and using --with-libiconv-type=static, and with libiconv.so
installed and using --without-libiconv-prefix (which still fails).
I'm not entirely happy about the fact that libtool's LTLIBICONV adds an
rpath to libstdc++.so, but that can be avoided (as documented by this
patch) and I don't really see a better solution. Another option would be
to use -l:libiconv.a if configure defines LTLIBICONV to non-empty and
the linker supports it, which would *force* the use of a static lib. But
that seems unnecessarily hostile; not all users will dislike the rpath
solution. The proposed patch makes it Just Work⢠for users who (for
whatever reason) have installed libiconv, while also allowing them to do
something more sensible if they care enough to do so.
Thoughts?
-- >8 --
This fixes missing libiconv symbols when libstdc++ is built on a system
that has libiconv installed. If the libiconv headers are found then
libstdc++ depends on libiconv_open etc instead of libc's iconv_open. But
without this fix libstdc++ is not linked to the libiconv library that
provides the definitions of those symbols.
As discussed in PR 93602 this changed means that libstdc++.so.6 might
have an rpath pointing to the location of the libiconv.so library. If
that is not desired, then GCC must be configured to link to a static
libiconv.a instead, using either --with-libiconv-type=static or an
in-tree build of libiconv.
libstdc++-v3/ChangeLog:
PR libstdc++/93602
* doc/xml/manual/prerequisites.xml: Document libiconv
workarounds.
* doc/html/manual/setup.html: Regenerate.
* src/Makefile.am (CXXLINK): Add $(LTLIBICONV).
* src/Makefile.in: Regenerate.
---
diff --git a/libstdc++-v3/doc/xml/manual/prerequisites.xml
b/libstdc++-v3/doc/xml/manual/prerequisites.xml
index 22e90a7e79d..8799487c821 100644
--- a/libstdc++-v3/doc/xml/manual/prerequisites.xml
+++ b/libstdc++-v3/doc/xml/manual/prerequisites.xml
@@ -48,6 +48,56 @@
<varlistentry>
<term>linux</term>
+ <listitem>
+ <para>
+ The 'gnu' locale model makes use of <function>iconv</function>
+ for character set conversions. The relevant functions are provided
+ by Glibc and so are always available, however they can also be
+ provided by the separate GNU libiconv library. If GNU libiconv is
+ found when GCC is built (e.g., because its headers are installed
+ in <filename class="directory">/usr/local/include</filename>)
+ then the <filename>libstdc++.so.6</filename> library will have a
+ run-time dependency on <filename>libiconv.so.2</filename>.
+ If you do not want that run-time dependency then you should do
+ one of the following:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Uninstall the libiconv headers before building GCC.
+ Glibc already provides <function>iconv</function> so you should
+ not need libiconv anyway.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <link linkend="https://www.gnu.org/software/libiconv/#downloading";>
+ Download</link> the libiconv sources and extract them into the
+ top level of the GCC source tree, e.g.,
+ </para>
+<programlisting>
+wget https://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.16.tar.gz
+tar xf libiconv-1.16.tar.gz
+ln -s libiconv-1.16 libiconv
+</programlisting>
+ <para>
+ This will build libiconv as part of building GCC and link to
+ it statically, so there is no <filename>libiconv.so.2</filename>
+ dependency.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Configure GCC with <option>--with-libiconv-type=static</option>.
+ This requires the static <filename>libiconv.a</filename> library,
+ which is not installed by default. You might need to reinstall
+ libiconv using the <option>--enable-static</option> configure
+ option to get the static library.
+ </para>
+ </listitem>
+ </itemizedlist>
+ </listitem>
+
<listitem>
<para>
If GCC 3.1.0 or later on is being used on GNU/Linux, an attempt
diff --git a/libstdc++-v3/src/Makefile.am b/libstdc++-v3/src/Makefile.am
index 18f57632c3d..9c3f4aca655 100644
--- a/libstdc++-v3/src/Makefile.am
+++ b/libstdc++-v3/src/Makefile.am
@@ -278,7 +278,9 @@ CXXLINK = \
$(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) \
--mode=link $(CXX) \
$(VTV_CXXLINKFLAGS) \
- $(OPT_LDFLAGS) $(SECTION_LDFLAGS) $(AM_CXXFLAGS) $(LTLDFLAGS) -o $@
+ $(OPT_LDFLAGS) $(SECTION_LDFLAGS) $(AM_CXXFLAGS) \
+ $(LTLDFLAGS) $(LTLIBICONV) \
+ -o $@
# Symbol versioning for shared libraries.
if ENABLE_SYMVERS
