Doc: check for w3m existence

w3m is called as non-last command in pipelines. A missing w3m
creates empty output and Make doesn't get it, because the last command
of the pipe (e.g. Tidytxt) doesn't return failure on empty input.

diff --git a/doc/doc-docbook/Makefile b/doc/doc-docbook/Makefile
index d835db9edfa961036999ed9a6b80148c61ff96e3..ee97257b64d98915a0ceef7a9bbe7ae86a4ddb89 100644 (file)
--- a/doc/doc-docbook/Makefile
+++ b/doc/doc-docbook/Makefile
@@ -96,6 +96,7 @@ filter.txt:   filter-txt.xml Tidytxt MyStyle-txt-html.xsl MyStyle-html.xsl \
                 MyStyle.xsl
              /bin/rm -rf filter-txt.html
              xmlto -x MyStyle-txt-html.xsl html-nochunks filter-txt.xml
+             command -v w3m >/dev/null
              LC_ALL=C w3m -dump filter-txt.html | ./Tidytxt >filter.txt
              ./SanityTestText filter.txt
 
@@ -181,9 +182,11 @@ spec.utf8: spec-txt.html Tidytxt
                @grep -iq 'LC_CTYPE=.*utf-\?8' local_params || { \
                        echo 'your current locale does not support UTF-8' >&2; \
                        false; }
+               command -v w3m >/dev/null
                w3m -dump $< | ./Tidytxt -utf8 >$@
 
 spec.txt: spec-txt.html Tidytxt
+             command -v w3m >/dev/null
              LC_ALL=C w3m -dump $< | ./Tidytxt >$@
              ./SanityTestText spec.txt
 
@@ -270,6 +273,7 @@ test.txt:     test-txt.xml Tidytxt MyStyle-txt-html.xsl MyStyle-html.xsl \
                 MyStyle.xsl
              /bin/rm -rf test-txt.html
              xmlto -x MyStyle-txt-html.xsl html-nochunks test-txt.xml
+             command -v w3m >/dev/null
              w3m -dump test-txt.html | Tidytxt >test.txt
 
 # I have not found a way of making docbook2texi write its output anywhere