[groff] 15/16: Weaken build dependency on TeX.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 31f64af693b077b846ac2540f4ea2baf95c4ef10
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Thu Jun 9 16:45:42 2022 -0500

    Weaken build dependency on TeX.
    
    [build]: Weaken dependency on TeX, instead using it (to generate the DVI
    and PDF forms of our Texinfo manual) only if it is available.
    
    * m4/groff.m4 (GROFF_USE_TEX_CHECK): Check for presence of 'tex'
      executable in path.  Set shell variable `groff_use_tex` to "yes" if
      present, and "no" otherwise.  This check runs only if the 'makeinfo'
      and 'texi2dvi' version checks have already passed.
    
    * configure.ac: Run the new check.  Set Automake conditional `USE_TEX`
      only if shell variable `groff_use_tex` is "yes".  Report whether
      "groff.dvi" and "groff.pdf" are (re-)buildable.
    
    * doc/doc.am: Parameterize names of groff.{dvi,pdf} targets as Make
      macros `GROFF_DVI` and `GROFF_PDF`.  Define them only if `USE_TEX`.
      Do _not_ update `EXTRA_DIST` macro; leave the literal file names there
      because we require that distribution archives contain these files.
    
      (.texi.dvi, .texi.pdf): Update suffix rules to check `USE_TEX` and
      fail, complaining of missing 'tex' program, if these targets are
      attempted without it being true.  Only manually specifying the file
      names as targets to 'make' or attempting to generate a distribution
      archive without TeX present should cause these errors.
    
    * INSTALL.REPO: Update dependency information.
    
    Fixes <https://savannah.gnu.org/bugs/?62592>.  Thanks to Deri James for
    the report.
---
 ChangeLog    | 32 ++++++++++++++++++++++++++++++++
 INSTALL.REPO |  6 +++++-
 configure.ac |  3 +++
 doc/doc.am   | 23 +++++++++++++++++++----
 m4/groff.m4  | 10 ++++++++++
 5 files changed, 69 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 1179e02e..ce454eb9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,35 @@
+2022-06-09  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       [build]: Weaken dependency on TeX, instead using it (to generate
+       the DVI and PDF forms of our Texinfo manual) only if it is
+       available.
+
+       * m4/groff.m4 (GROFF_USE_TEX_CHECK): Check for presence of 'tex'
+       executable in path.  Set shell variable `groff_use_tex` to "yes"
+       if present, and "no" otherwise.  This check runs only if the
+       'makeinfo' and 'texi2dvi' version checks have already passed.
+
+       * configure.ac: Run the new check.  Set Automake conditional
+       `USE_TEX` only if shell variable `groff_use_tex` is "yes".
+       Report whether "groff.dvi" and "groff.pdf" are (re-)buildable.
+
+       * doc/doc.am: Parameterize names of groff.{dvi,pdf} targets as
+       Make macros `GROFF_DVI` and `GROFF_PDF`.  Define them only if
+       `USE_TEX`.  Do _not_ update `EXTRA_DIST` macro; leave the
+       literal file names there because we require that distribution
+       archives contain these files.
+       (.texi.dvi, .texi.pdf): Update suffix rules to check `USE_TEX`
+       and fail, complaining of missing 'tex' program, if these targets
+       are attempted without it being true.  Only manually specifying
+       the file names as targets to 'make' or attempting to generate a
+       distribution archive without TeX present should cause these
+       errors.
+
+       * INSTALL.REPO: Update dependency information.
+
+       Fixes <https://savannah.gnu.org/bugs/?62592>.  Thanks to Deri
+       James for the report.
+
 2022-06-09  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        * doc/doc.am (.texi.dvi, .texi.pdf, $(DOC_GNU_EPS)): Quote names
diff --git a/INSTALL.REPO b/INSTALL.REPO
index 066cb77d..e6cf192c 100644
--- a/INSTALL.REPO
+++ b/INSTALL.REPO
@@ -35,7 +35,11 @@ are several others.
 * groff's Texinfo manual is generated in several formats: GNU Info,
   HTML, plain text, TeX DVI, and PDF.  The former three require
   'makeinfo' from GNU Texinfo 5.0 or later.  The latter two additionally
-  require a TeX installation, such as TeX Live.
+  require a TeX installation, such as TeX Live.  If TeX is not
+  installed, the DVI and PDF formats of the manual cannot be generated.
+  This will cause a build failure only if the Texinfo source file
+  "groff.texi" is updated and the make(1) "dist" or relevant file
+  targets are manually specified.
 
 * You will need the 'xpmtoppm', 'pnmdepth', and 'pnmtops' programs from
   the Netpbm distribution.
diff --git a/configure.ac b/configure.ac
index b2d6df94..ef06727a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -70,6 +70,7 @@ GROFF_PROG_YACC
 GROFF_PROG_M4
 GROFF_PROG_MAKEINFO
 GROFF_PROG_TEXI2DVI
+GROFF_USE_TEX_CHECK
 AC_PROG_RANLIB
 GROFF_INSTALL_SH
 GROFF_INSTALL_INFO
@@ -207,6 +208,7 @@ AM_CONDITIONAL([USE_GROFF_ALLOCATOR],
 AM_CONDITIONAL([HAVE_URW_FONTS], [test "$groff_have_urw_fonts" = yes ])
 AM_CONDITIONAL([HAVE_PDFTOOLS], [test "$groff_have_pdftools" = yes ])
 AM_CONDITIONAL([HAVE_TEXI2DVI], [test "$groff_have_texi2dvi" = yes ])
+AM_CONDITIONAL([USE_TEX], [test "$groff_use_tex" = yes ])
 
 AC_CONFIG_FILES([Makefile])
 AC_CONFIG_FILES([test-groff], [chmod +x test-groff])
@@ -244,6 +246,7 @@ echo "\
  'groff -l' uses print spooler    : $groff_have_spooler
  use URW fonts for PDF output     : $groff_have_urw_fonts
  preconv can use uchardet library : $groff_have_uchardet
+ can build groff.dvi, groff.pdf   : $groff_use_tex
  tests can use poppler PDF tools  : $groff_have_pdftools
 ----------------------------------------------------------------------"
 
diff --git a/doc/doc.am b/doc/doc.am
index 77c60779..cede334d 100644
--- a/doc/doc.am
+++ b/doc/doc.am
@@ -503,8 +503,13 @@ endif
 #info_TEXINFOS = doc/groff.texi
 #doc_groff_TEXINFOS = doc/fdl.texi
 
-all: doc/groff.info doc/groff.txt doc/groff.html doc/groff.dvi \
-  doc/groff.pdf
+if USE_TEX
+GROFF_DVI = doc/groff.dvi
+GROFF_PDF = doc/groff.pdf
+endif
+
+all: doc/groff.info doc/groff.txt doc/groff.html $(GROFF_DVI) \
+  $(GROFF_PDF)
 
 # Distribute the manual in source form as well.
 EXTRA_DIST += doc/groff.texi doc/fdl.texi
@@ -561,6 +566,7 @@ EXTRA_DIST += doc/groff.dvi doc/groff.pdf
 # 'install-pdf' and 'install-dvi' are standard Automake targets.
 .texi.dvi:
 if HAVE_TEXI2DVI
+if USE_TEX
        $(AM_V_at)$(MKDIR_P) $(doc_builddir)
        $(AM_V_GEN)LANG=C \
        LC_ALL=C \
@@ -569,14 +575,19 @@ if HAVE_TEXI2DVI
        FORCE_SOURCE_DATE=1 \
        $(PROG_TEXI2DVI) -e --batch --build-dir=doc/`basename $@`.t2d \
          -o $@ $<
+else
+       @echo "program 'tex' is missing; cannot generate $@" >&2; \
+       exit 1
+endif # USE_TEX
 else
        @echo "program 'texi2dvi' is missing or too old;" \
          "cannot generate $@" >&2; \
        exit 1
-endif
+endif # HAVE_TEXI2DVI
 
 .texi.pdf:
 if HAVE_TEXI2DVI
+if USE_TEX
        $(AM_V_at)$(MKDIR_P) $(doc_builddir)
        $(AM_V_GEN)LANG=C \
        LC_ALL=C \
@@ -584,11 +595,15 @@ if HAVE_TEXI2DVI
        MAKEINFO='$(MAKEINFO) -I $(doc_srcdir)' \
        $(PROG_TEXI2DVI) -e --batch --pdf \
          --build-dir=doc/`basename $@`.t2p -o $@ $<
+else
+       @echo "program 'tex' is missing; cannot generate $@" >&2; \
+       exit 1
+endif # USE_TEX
 else
        @echo "program 'texi2dvi' is missing or too old;" \
          "cannot generate $@" >&2; \
        exit 1
-endif
+endif # HAVE_TEXI2DVI
 
 install-doc: install-pdf install-html
 
diff --git a/m4/groff.m4 b/m4/groff.m4
index a72acb5f..8740ce10 100644
--- a/m4/groff.m4
+++ b/m4/groff.m4
@@ -161,6 +161,16 @@ AC_DEFUN([GROFF_PROG_TEXI2DVI], [
   fi
 ])
 
+# 'texi2dvi' can be installed without TeX itself, so check for a 'tex'
+# executable independently.
+
+AC_DEFUN([GROFF_USE_TEX_CHECK], [
+  AC_REQUIRE([GROFF_PROG_TEXI2DVI])
+  AC_CHECK_PROG([PROG_TEX], [tex], [found], [missing])
+  groff_use_tex=no
+  test "$PROG_TEX" = found && groff_use_tex=yes
+])
+
 # grohtml needs the following programs to produce images from tbl(1)
 # tables and eqn(1) equations.