[build]: Refactor generation of "freeeuro.pfa" to make more economical
use of existing infrastructure, per a suggestion from Deri James.  This
also puts the file where gropdf's "download" file can find it when
running it in a separate build directory.  We use it to generate
"groff-man-pages.pdf".

* font/devps/freeeuro.pfa: Rename this...
* font/devps/freeeuro.ps: ...to this.  We can now use the suffix rule
  that also applies to "symbolsl.ps" and "zapfdr.ps".

* font/devps/devps.am (DEVPSFONTFILES): Move "freeeuro.pfa" from here...
  (DEVPSFONTFILES_GENERATED): ...to here.
  (EXTRA_DIST): Ship the "new" "freeeuro.ps" file.

This restores the embedding of this font in the groff_char(7) man page
in "groff-man-pages.pdf".

* font/devps/psstrip.sed: Stop stripping comment lines, in general
  instead of preserving only ones that use the form in the Document
  Structuring Coventions.  This way we won't strip copyright notices,
  like Werner Lemberg's in the FreeEuro font.  Thanks to Deri James for
  pointing this out.

* font/devps/devps.am: Refactor.  Turn two identical target rules into a
  (BSD-make-style, old-fashioned) pattern rule.

* font/devps/generate/textmap: Rename from this...
* font/devps/generate/text.map: ...to this.

* font/devpdf/Foundry.in:
* font/devpdf/devpdf.am (DEVPDFFONTMAP_1):
* font/devps/devps.am (DEVPSGENFILES):
* font/devps/generate/Makefile (TEXTMAP):
* src/devices/gropdf/gropdf.1.man:
* src/devices/grops/grops.1.man:
* src/utils/afmtodit/afmtodit.1.man: Reflect rename.

* font/devps/generate/lgreekmap: Rename from this...
* font/devps/generate/slanted-symbol.map: ...to this.

* font/devps/devps.am (DEVPSGENFILES):
* font/devps/generate/Makefile (SS):
* src/utils/afmtodit/afmtodit.1.man: Reflect rename.

* font/devps/generate/dingbats.rmap: Rename from this...
* font/devps/generate/dingbats-reversed.map: ...to this.

* font/devps/devps.am (DEVPSGENFILES):
* font/devps/generate/Makefile (ZDR):
* src/utils/afmtodit/afmtodit.1.man: Reflect rename.

[build]: Name and place PS->groff glyph name maps consistently.

* font/devps/symbolmap: Rename from this...
* font/devps/generate/symbol.map: ...to this.

* font/devpdf/devpdf.am (font/devpdf/map/symbolmap): Rename target...
  (font/devpdf/map/symbol.map): ...to this.
  (font/devpdf/map/symbol.map): Copy "devps" version of file from its
  new location in the "generate" subdirectory.

* font/devpdf/Foundry.in: Reflect rename.

* font/devps/generate/Makefile (symbolmap): Rename target...
  ($(srcdir)/symbol.map): ...to this.

* font/devps/devps.am (DEVPSGENFILES, EXTRA_DIST):
* font/devps/generate/Makefile (S, EURO $(SPECIALFONTS), clean):
* src/utils/afmtodit/afmtodit.1.man: Reflect rename and relocation.

* font/devps/S:
* font/devps/symbolmap: Drop excess mapping of `*U` special character.
  groff maps it to the Adobe Glyph List name 'Upsilon1'.  (The AGL
  'Upsilon' is a homoglyph of the Latin capital 'Y'.)
* PROBLEMS: De-document build-time warning, now resolved.

[build]: Reduce and rationalize in-tree document dependencies.  This
eliminates spurious rebuilds of numerous documents (including the
380+-page groff-man-pages collections).  It also fixes missing
dependencies when using the build's groff to generate PostScript
documents.

* .gitignore: Drop old name of devpdf stamp file.

* doc/.gitignore: Drop now-unused "example.stamp" file.

* doc/doc.am (PROCESSEDDOCFILES_HTML, PROCESSEDDOCFILES_PDF,
  PROCESSEDDOCFILES_TXT): Add new macros grouping targets by the
  format/output driver used to produce them, to better organize
  dependencies for their generation.

  (PROCESSEDDOCFILES): Redefine as simply the expansions of the
  foregeoing.

  (PROCESSEDFILES_DEPS_HTML, PROCESSEDFILES_DEPS_HTML,
  PROCESSEDFILES_DEPS_PDF, PROCESSEDFILES_DEPS_TXT): Add new macros
  defining prerequisites for production of the corresponding output
  document formats.

  ($(PROCESSEDDOCFILES_HTML), $(PROCESSEDDOCFILES_PDF),
  $(PROCESSEDDOCFILES_PS), $(PROCESSEDDOCFILES_TXT)): Declare the
  dependencies using expansions of the foregoing macros.

  (MOSTLYCLEANFILES): Drop "doc/automake.pdf", now part of
  `PROCESSEDDOCFILES_PDF`.

  (doc/automake.pdf): Drop dependencies already supplied by
  `PROCESSEDFILES_DEPS_PDF`.

  (HTMLDOCFILES): Drop macro.  "doc/pic.html" is now in the expansion of
  `PROCESSEDDOCFILES_HTML`.

  (htmlpic_DATA): Redefine as expansion of `PROCESSEDDOCFILES_HTML`
  instead of `HTMLDOCFILES`.

  (PROCESSEDEXAMPLEFILES_HTML) [BUILD_HTML]: Define as
  "doc/webpage.html", otherwise as empty.

  (PROCESSEDEXAMPLEFILES_PS): Contain "doc/webpage.ps" and
  "doc/grnexampl.ps".

  (PROCESSEDEXAMPLEFILES): Redefine as expansions of
  `PROCESSEDEXAMPLEFILES_HTML` and `PROCESSEDEXAMPLEFILES_PS`.

  ($(PROCESSEDEXAMPLEFILES_HTML), $(PROCESSEDEXAMPLEFILES_PS)): Declare
  dependencies using `PROCESSEDFILES_DEPS_HTML` and
  `PROCESSEDFILES_DEPS_PS`, respectively.

  (nodist_docexamples_DATA): Redefine macro as expansions of now-split
  macros `PROCESSEDEXAMPLEFILES_HTML` and `PROCESSEDEXAMPLEFILES_PS`.

  (HTMLEXAMPLEFILES): Drop macro.  "doc/webpage.html" is now in the
  expansion of `PROCESSEDDOCFILES_HTML`.

  (nodist_htmlexamples_DATA): Drop macro, no longer needed.

  ($(PROCESSEDDOCFILES_PS)): Relocated and redefined above.
  ($(PROCESSEDEXAMPLEFILES) $(PROCESSEDDOCFILES)): Drop overbroad
  dependency declarations in favor of the above.

  (MOSTLYCLEANFILES, doc/examples.stamp): Drop generation and removal of
  unnecessary stamp file.

  (doc/pic.html, doc/webpage.html): Add explicit dependency on required
  preprocessors.  Drop redundant and spurious dependencies.

* font/devhtml/devhtml.am (MOSTLYCLEANFILES, font/devhtml/stamp):
  Generate and remove stamp file to enable reliable target dependencies
  for build-time generation of HTML documents by groff.

* font/devpdf/devpdf.am (MOSTLYCLEANFILES, font/devpdf/stamp): Rename
  stamp file from "font/devpdf/build_font_files".

  (font/devpdf/stamp): Drop unnecessary dependency on "afmtodit".

* font/devps/devps.am (MOSTLYCLEANFILES, font/devps/stamp): Generate and
  remove stamp file to enable reliable target dependencies for
  build-time generation of PostScript documents by groff.

* font/devutf8/devutf8.am (MOSTLYCLEANFILES, font/devutf8/stamp):
  Generate and remove stamp file to enable reliable target dependencies
  for build-time generation of UTF-8-encoded text documents by groff.

* contrib/hdtbl/hdtbl.am (HDTBLPROCESSEDEXAMPLEFILES): Add dependency on
  devps stamp file since the files' target rule generates PostScript
  with groff.

* contrib/mom/mom.am ($(MOMPROCESSEDEXAMPLEFILES)): Depend on new name
  for devpdf stamp file.

* contrib/sboxes/sboxes.am ($(sboxes_builddir)/msboxes.pdf): Depend on
  new name for devpdf stamp file.

Fixes <https://savannah.gnu.org/bugs/?62084>; thanks to Sergei
Trofimovich for the report.  Also fixes
<https://savannah.gnu.org/bugs/?62297>; thanks to Bjarni Ingi Gislason
for the report.

Tested with the following script.

	#!/bin/sh

	set -e

	test -d build
	cd build

	for file in \
	    contrib/hdtbl/examples/chess_board.ps \
	    contrib/hdtbl/examples/col_rowspan_colors.ps \
	    contrib/hdtbl/examples/color_boxes.ps \
	    contrib/hdtbl/examples/color_nested_tables.ps \
	    contrib/hdtbl/examples/color_table_cells.ps \
	    contrib/hdtbl/examples/color_transitions.ps \
	    contrib/hdtbl/examples/fonts_n.ps \
	    contrib/hdtbl/examples/fonts_x.ps \
	    contrib/hdtbl/examples/mixed_pickles.ps \
	    contrib/hdtbl/examples/rainbow.ps \
	    contrib/hdtbl/examples/short_reference.ps \
	    contrib/mom/examples/copyright-chapter.pdf \
	    contrib/mom/examples/copyright-default.pdf \
	    contrib/mom/examples/letter.pdf \
	    contrib/mom/examples/mom-pdf.pdf \
	    contrib/mom/examples/mon_premier_doc.pdf \
	    contrib/mom/examples/sample_docs.pdf \
	    contrib/mom/examples/slide-demo.pdf \
	    contrib/mom/examples/typesetting.pdf \
	    contrib/sboxes/msboxes.pdf \
	    doc/automake.pdf \
	    doc/grnexmpl.ps \
	    doc/groff-man-pages.pdf \
	    doc/groff-man-pages.utf8.txt \
	    doc/meintro.ps \
	    doc/meintro_fr.ps \
	    doc/meref.ps \
	    doc/ms.ps \
	    doc/pic.html \
	    doc/pic.ps \
	    doc/webpage.ps
	do
	    make -j clean
	    make -j "$file"
	done

* doc/doc.am: Put spaces around (Auto)make variable assignments, for
  consistency with the rest of this .am file, and our others.

* font/devpdf/devpdf.am (font/devpdf/build_font_files): Use shell '>'
  operator instead of touch(1).

* font/devhtml/devhtml.am (font/devhtml/DESC):
* font/devps/devps.am (font/devps/DESC): Construct target in temporary
  file, since doing so is a multi-step process, moving it to the target
  name when it is complete and usable by dependencies.

Also fix indentation and trailing whitespace nits.