Moved the intricacies of the perl interface build into its own makefile

that now functions as a wrapper around the MakeMaker stuff. It might
even behave sensically when we have separate build dirs. Same for plperl,
which of course still doesn't work very well. Made sure that plperl
respects the choice of --libdir.

Added --with-python to automatically build and install the Python interface.
Works similarly to the Perl5 stuff.

Moved the burden of the distclean targets lower down into the source tree.
Eventually, each make file should have its own.

Added automatic remaking of makefiles and configure. Currently only for the
top-level because of a bug(?) in Autoconf. Use GNU `missing' to work around
missing autoconf and aclocal. Start factoring out macros into their own
config/*.m4 files to increase readability and organization.

configure.in

@@ -4,7 +4,10 @@ AC_PREFIX_DEFAULT(/usr/local/pgsql)
 AC_CONFIG_HEADER(src/include/config.h)
 
 AC_PREREQ(2.13)
-AC_CONFIG_AUX_DIR(config)
+AC_CONFIG_AUX_DIR(`pwd`/config)
+
+mkinstalldirs="\$(SHELL) \$(top_srcdir)/config/mkinstalldirs"
+AC_SUBST(mkinstalldirs)
 
 AC_CANONICAL_HOST
 
@@ -370,19 +373,35 @@ AC_ARG_WITH(tkconfig,
     ]
 )
 
-dnl We exclude perl support unless we override it with --with-perl
-AC_MSG_CHECKING(setting USE_PERL)
-AC_ARG_WITH(
-   perl,
-   [  --with-perl             build Perl interface and plperl ],
-   [
-	case "$withval" in
-	y | ye | yes)	USE_PERL=true; AC_MSG_RESULT(enabled) ;;
-	*)		USE_PERL=false; AC_MSG_RESULT(disabled) ;;
-	esac
-   ],
-   [ USE_PERL=false; AC_MSG_RESULT(disabled) ]
-)
+
+dnl
+dnl Optionally build Perl modules (Pg.pm and PL/Perl)
+dnl
+AC_MSG_CHECKING(whether to build Perl modules)
+AC_ARG_WITH(perl, [  --with-perl             build Perl interface and plperl],
+[if test x"${withval}" = x"yes" ; then
+  AC_MSG_RESULT(yes)
+else
+  AC_MSG_RESULT(no)
+fi],
+[AC_MSG_RESULT(no)])
+AC_SUBST(with_perl)
+
+
+dnl
+dnl Optionally build Python interface module
+dnl
+AC_MSG_CHECKING(whether to build Python modules)
+AC_ARG_WITH(python, [  --with-python           build Python interface module],
+[if test x"${withval}" = x"yes" ; then
+  AC_MSG_RESULT(yes)
+  PGAC_PROG_PYTHON
+  PGAC_PATH_PYTHONDIR
+else
+  AC_MSG_RESULT(no)
+fi],
+[AC_MSG_RESULT(no)])
+AC_SUBST(with_python)
 
 dnl We include odbc support unless we disable it with --with-odbc=false
 AC_MSG_CHECKING(setting USE_ODBC)
@@ -543,7 +562,6 @@ AC_SUBST(DL_LIB)
 AC_SUBST(USE_TCL)
 AC_SUBST(USE_TK)
 AC_SUBST(WISH)
-AC_SUBST(USE_PERL)
 AC_SUBST(USE_ODBC)
 AC_SUBST(MULTIBYTE)
 
@@ -646,6 +664,8 @@ AC_SUBST(INSTL_SHLIB_OPTS)
 AC_SUBST(INSTL_EXE_OPTS)
 
 AC_PROG_AWK
+AM_MISSING_PROG(AUTOCONF, autoconf, [\${SHELL} \${top_srcdir}/config])
+AM_MISSING_PROG(ACLOCAL, aclocal, [\${SHELL} \${top_srcdir}/config])
 
 dnl Check the option to echo to inhibit newlines.
 ECHO_N_OUT=`echo -n "" | wc -c`
@@ -680,7 +700,6 @@ broken as well.)
         fi
 fi
 AC_PROG_LN_S
-AC_PROG_MAKE_SET
 AC_PROG_RANLIB
 AC_PATH_PROG(find, find)
 AC_PATH_PROG(tar, tar)
@@ -690,7 +709,6 @@ AC_PATH_PROG(xargs, xargs)
 AC_PATH_PROGS(GZCAT, gzcat zcat, gzcat)
 AC_CHECK_PROGS(PERL, perl,)
 AC_PROG_YACC
-AC_SUBST(YFLAGS)
 
 
 AC_CHECK_LIB(sfio,     main)
@@ -1403,16 +1421,21 @@ AC_OUTPUT(
 	src/bin/pgtclsh/mkMakefile.tkdefs.sh
 	src/bin/psql/Makefile
 	src/include/version.h
+	src/interfaces/Makefile
 	src/interfaces/libpq/Makefile
 	src/interfaces/ecpg/lib/Makefile
 	src/interfaces/ecpg/preproc/Makefile
+	src/interfaces/perl5/GNUmakefile
 	src/interfaces/libpq++/Makefile
 	src/interfaces/libpgeasy/Makefile
 	src/interfaces/libpgtcl/Makefile
 	src/interfaces/odbc/GNUmakefile
 	src/interfaces/odbc/Makefile.global
+	src/interfaces/python/GNUmakefile
+	src/pl/Makefile
 	src/pl/plpgsql/src/Makefile
 	src/pl/plpgsql/src/mklang.sql
 	src/pl/tcl/mkMakefile.tcldefs.sh
+	src/pl/plperl/GNUmakefile
 	src/test/regress/GNUmakefile
 )