Rework directory structure to use GNU-recommended "src" directory.

Move the source code (other than glob) into the "src" subdirectory.
Update all scripting and recommendations to support this change.

* *.c, *.h, w32/*: Move to src/
* configure.ac, Makefile.am, maintMakefile: Locate new source files.
* Basic.mk.template, mk/*: Update for new source file locations.
* NEWS, README.DOS.template: Update for new locations.
* build.template, build_w32.bat, builddos.bat: Ditto.
* po/POTFILES.in: Ditto
* tests/run_make_tests.pl, tests/scripts/features/load*: Ditto.
* make.1: Move to doc.
* mk/VMS.mk: Add support for building on VMS (hopefully).
* makefile.vms, prepare_w32.bat: Remove.
* SCOPTIONS: Update to define HAVE_CONFIG_H

src/loadapi.c

@@ -0,0 +1,82 @@
+/* API for GNU Make dynamic objects.
+Copyright (C) 2013-2017 Free Software Foundation, Inc.
+This file is part of GNU Make.
+
+GNU Make is free software; you can redistribute it and/or modify it under the
+terms of the GNU General Public License as published by the Free Software
+Foundation; either version 3 of the License, or (at your option) any later
+version.
+
+GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "makeint.h"
+
+#include "filedef.h"
+#include "variable.h"
+#include "dep.h"
+
+/* Allocate a buffer in our context, so we can free it.  */
+char *
+gmk_alloc (unsigned int len)
+{
+  return xmalloc (len);
+}
+
+/* Free a buffer returned by gmk_expand().  */
+void
+gmk_free (char *s)
+{
+  free (s);
+}
+
+/* Evaluate a buffer as make syntax.
+   Ideally eval_buffer() will take const char *, but not yet.  */
+void
+gmk_eval (const char *buffer, const gmk_floc *gfloc)
+{
+  /* Preserve existing variable buffer context.  */
+  char *pbuf;
+  unsigned int plen;
+  char *s;
+  floc fl;
+  floc *flp;
+
+  if (gfloc)
+    {
+      fl.filenm = gfloc->filenm;
+      fl.lineno = gfloc->lineno;
+      fl.offset = 0;
+      flp = &fl;
+    }
+  else
+    flp = NULL;
+
+  install_variable_buffer (&pbuf, &plen);
+
+  s = xstrdup (buffer);
+  eval_buffer (s, flp);
+  free (s);
+
+  restore_variable_buffer (pbuf, plen);
+}
+
+/* Expand a string and return an allocated buffer.
+   Caller must call gmk_free() with this buffer.  */
+char *
+gmk_expand (const char *ref)
+{
+  return allocated_variable_expand (ref);
+}
+
+/* Register a function to be called from makefiles.  */
+void
+gmk_add_function (const char *name, gmk_func_ptr func,
+                  unsigned int min, unsigned int max, unsigned int flags)
+{
+  define_new_function (reading_file, name, min, max, flags, func);
+}