[PATCH v2 5/8] docs: exclude documentation for commands that have been excluded

["Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

When building with certain build options, some commands are excluded
from the build. For example, `git-credential-cache` is skipped when
building with `NO_UNIX_SOCKETS`.

Let's not build or package documentation for those excluded commands.

This issue was pointed out rightfully when running `make check-docs` on
Windows, where we do not yet have Unix sockets, and therefore the
`credential-cache` command is excluded (yet its documentation was built
and shipped).

Note: building the documentation via `make -C Documentation` leaves the
build system with no way to determine which commands have been
excluded. If called thusly, we gracefully fail to exclude their
documentation. Only when building the documentation via the top-level
Makefile will it get excluded properly, or after building
`Documentation/GIT-EXCLUDED-PROGRAMS` manually.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 Documentation/.gitignore | 1 +
 Documentation/Makefile   | 3 +++
 Makefile                 | 9 +++++++++
 3 files changed, 13 insertions(+)

diff --git a/Documentation/.gitignore b/Documentation/.gitignore
index 3ef54e0adb..ea27148c59 100644
--- a/Documentation/.gitignore
+++ b/Documentation/.gitignore
@@ -13,3 +13,4 @@ mergetools-*.txt
 manpage-base-url.xsl
 SubmittingPatches.txt
 tmp-doc-diff/
+/GIT-EXCLUDED-PROGRAMS
diff --git a/Documentation/Makefile b/Documentation/Makefile
index af0e2cf11a..e22ea2f57c 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -7,7 +7,10 @@ ARTICLES =
 SP_ARTICLES =
 OBSOLETE_HTML =
 
+-include GIT-EXCLUDED-PROGRAMS
+
 MAN1_TXT += $(filter-out \
+		$(patsubst %,%.txt,$(EXCLUDED_PROGRAMS)) \
 		$(addsuffix .txt, $(ARTICLES) $(SP_ARTICLES)), \
 		$(wildcard git-*.txt))
 MAN1_TXT += git.txt
diff --git a/Makefile b/Makefile
index d83104d884..6f90cec590 100644
--- a/Makefile
+++ b/Makefile
@@ -2451,6 +2451,14 @@ $(VCSSVN_LIB): $(VCSSVN_OBJS)
 
 export DEFAULT_EDITOR DEFAULT_PAGER
 
+Documentation/GIT-EXCLUDED-PROGRAMS: FORCE
+	@EXCLUDED='EXCLUDED_PROGRAMS := $(EXCLUDED_PROGRAMS)'; \
+	    if test x"$$EXCLUDED" != \
+		x"`cat Documentation/GIT-EXCLUDED-PROGRAMS 2>/dev/null`" ; then \
+		echo >&2 "    * new documentation flags"; \
+		echo "$$EXCLUDED" >Documentation/GIT-EXCLUDED-PROGRAMS; \
+            fi
+
 .PHONY: doc man man-perl html info pdf
 doc: man-perl
 	$(MAKE) -C Documentation all
@@ -3030,6 +3038,7 @@ clean: profile-clean coverage-clean cocciclean
 	$(RM) $(GIT_TARNAME).tar.gz git-core_$(GIT_VERSION)-*.tar.gz
 	$(RM) $(htmldocs).tar.gz $(manpages).tar.gz
 	$(MAKE) -C Documentation/ clean
+	$(RM) Documentation/GIT-EXCLUDED-PROGRAMS
 ifndef NO_PERL
 	$(MAKE) -C gitweb clean
 	$(RM) -r perl/build/
-- 
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