hivexsh: Conditionally build for Mac OS X

OS X lacks open_memstream, causing hivexsh to fail to build.  This patch
defines HAVE_HIVEXSH, setting the only condition to open_memstream
existence.

Signed-off-by: Alex Nelson <ajnelson@cs.ucsc.edu>

Makefile.am

@@ -20,7 +20,11 @@ ACLOCAL_AMFLAGS = -I m4
 # Work around broken libtool.
 export to_tool_file_cmd=func_convert_file_noop
 
-SUBDIRS = gnulib/lib generator lib images gnulib/tests sh xml po
+SUBDIRS = gnulib/lib generator lib images gnulib/tests xml po
+
+if HAVE_HIVEXSH
+SUBDIRS += sh
+endif
 
 if HAVE_OCAML
 SUBDIRS += ocaml

configure.ac

@@ -137,7 +137,7 @@ dnl Check for mmap
 AC_REPLACE_FUNCS([mmap])
 
 dnl Functions.
-AC_CHECK_FUNCS([bindtextdomain])
+AC_CHECK_FUNCS([bindtextdomain open_memstream])
 
 dnl Check for pod2man and pod2text.
 AC_CHECK_PROG([POD2MAN],[pod2man],[pod2man],[no])
@@ -176,6 +176,9 @@ PKG_CHECK_MODULES([LIBXML2], [libxml-2.0])
 AC_SUBST([LIBXML2_CFLAGS])
 AC_SUBST([LIBXML2_LIBS])
 
+dnl hivexsh depends on open_memstream, which is absent on OS X.
+AM_CONDITIONAL([HAVE_HIVEXSH],[test "x$HAVE_OPEN_MEMSTREAM" = "xyes"])
+
 dnl Check for OCaml (optional, for OCaml bindings).
 AC_PROG_OCAML
 AC_PROG_FINDLIB