Further improvements of the configure system.

* Makefile.am (MU_COND_LIBMU_CPP): New cond.
(SUBDIRS): Use LIBMU_CPP_DIR
* configure.ac: Rename --disable-c++ to --disable-cxx: autoconf
cannot handle the former.
(MU_COND_LIBMU_CPP): New cond.
(AC_CONFIG_FILES): Add include/mailutils/cpp/Makefile
* include/mailutils/Makefile.am (nobase_pkginclude_HEADERS): Remove
(MU_COND_LIBMU_CPP): New cond.
(SUBDIRS): Add CPP_DIR
* include/mailutils/cpp/Makefile.am: Remove substitution vars.
(cppincludedir, cppinclude_HEADERS): New variables.
* include/mailutils/sys/Makefile.am (sysincludedir)
(sysinclude_HEADERS): New variables.

@@ -84,6 +84,10 @@ if MU_COND_LIBMU_SCM
   LIBMU_SCM_DIR = libmu_scm
 endif
 
+if MU_COND_LIBMU_CPP
+  LIBMU_CPP_DIR = libmu_cpp
+endif
+
 SUBDIRS = \
  mu-aux\
  include\
@@ -96,7 +100,7 @@ SUBDIRS = \
  lib\
  libmu_argp\
  libmu_cfg\
- libmu_cpp\
+ $(LIBMU_CPP_DIR)\
  $(LIBMU_SCM_DIR)\
  libmu_sieve\
  $(PYTHON_DIR)\

@@ -1141,10 +1141,10 @@ if test "$status_python" = yes; then
 fi
 AM_CONDITIONAL([MU_COND_PYTHON], [test "$status_python" = yes])
 
-AC_SUBST(MU_CXX_LTLIBRARIES_BUILD)
 AC_SUBST(MU_CXX_EXAMPLES_BUILD)
-MU_ENABLE_SUPPORT(c++,
+MU_ENABLE_SUPPORT(cxx,
   	          [MU_CXX_EXAMPLES_BUILD='$(MU_CXX_EXAMPLES_LIST)'])
+AM_CONDITIONAL([MU_COND_LIBMU_CPP], [test "$mu_cv_enable_cxx" = yes])
 
 # Default mailbox record
 # Note: 1. Support for mbox type is always enabled.
@@ -1332,6 +1332,7 @@ AC_CONFIG_FILES([
  include/Makefile
  include/mailutils/Makefile
  include/mailutils/sys/Makefile
+ include/mailutils/cpp/Makefile
  lib/Makefile
  libmu_argp/Makefile
  libmu_auth/Makefile

@@ -98,8 +98,9 @@ pkginclude_HEADERS = \
  vartab.h\
  version.h
 
-nobase_pkginclude_HEADERS = \
-  sys/nntp.h\
-  sys/pop3.h
-SUBDIRS = sys
+if MU_COND_LIBMU_CPP
+  CPP_DIR = cpp
+endif
+
+SUBDIRS = sys $(CPP_DIR)
 

@@ -16,7 +16,8 @@
 ##   along with GNU Mailutils; if not, write to the Free Software
 ##   Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
-MU_CXX_INCLUDES = \
+cppincludedir=$(pkgincludedir)/cpp
+cppinclude_HEADERS = \
  address.h\
  attribute.h\
  body.h\
@@ -41,6 +42,3 @@ MU_CXX_INCLUDES = \
  sieve.h\
  stream.h\
  url.h
-
-pkginclude_HEADERS = @MU_CXX_INCLUDES@
-EXTRA_HEADERS = '$(MU_CXX_INCLUDES)'

@@ -17,3 +17,7 @@
 ##   Foundation, Inc.  51 Franklin Street, Fifth Floor, Boston, MA
 ##   02110-1301 USA
 
+sysincludedir=$(pkgincludedir)/sys
+sysinclude_HEADERS = \
+  nntp.h\
+  pop3.h