[PATCH 1/5] configury: support DLLs on OS/2

Without -no-undefined, DLLs are not created on OS/2.

Without -avoid-version, M4 cannot load modules. Because on OS/2, links
without version-info to DLLs with version-info are not created, however
m4 tries to load modules without version-info.

* Makefile.am (AM_LDFLAGS): Add OS2_LDFLAGS.
(module_ldflags): Add -avoid-version on OS/2.
* configure.ac (OS2_LDFLAGS): Add -no-undefined on *-*-os2*.
(HAVE_OS2): Define it on os2*.
---
 Makefile.am  | 5 ++++-
 configure.ac | 5 +++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/Makefile.am b/Makefile.am
index e9ec90d..72bdfab 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -41,7 +41,7 @@ changelog_old		= $(srcdir)/ChangeLog.old
 # See http://lists.gnu.org/archive/html/libtool-patches/2007-02/msg00062.html
 AM_CPPFLAGS	= -I$(srcdir) -I.
 AM_CFLAGS	= $(WARN_CFLAGS) $(WERROR_CFLAGS)
-AM_LDFLAGS	= -export-dynamic -export-symbols-regex ".*"
+AM_LDFLAGS	= -export-dynamic -export-symbols-regex ".*" $(OS2_LDFLAGS)
 EXTRA_DIST	=
 BUILT_SOURCES	=
 CLEANFILES	=
@@ -149,6 +149,9 @@ MOSTLYCLEANFILES += src/getopt.h src/getopt.h-t
 ## -------- ##
 
 module_ldflags	= -module $(AM_LDFLAGS)
+if HAVE_OS2
+module_ldflags	+= -avoid-version
+endif
 module_libadd	= m4/libm4.la
 
 noinst_HEADERS	= modules/m4.h
diff --git a/configure.ac b/configure.ac
index 2fe6d9e..d05f637 100644
--- a/configure.ac
+++ b/configure.ac
@@ -275,6 +275,11 @@ AM_CONDITIONAL([USE_GMP], [test "x$USE_GMP" = xyes])
 M4_SYSCMD
 
 
+AS_CASE([$host], [*-*-os2*], [OS2_LDFLAGS="-no-undefined"])
+AC_SUBST([OS2_LDFLAGS])
+AM_CONDITIONAL([HAVE_OS2], [test -z "${host_os##os2*}"])
+
+
 ## -------- ##
 ## Outputs. ##
 ## -------- ##
-- 
1.8.5.2