help -a: do not list commands that are excluded from the build

When built with NO_CURL or with NO_UNIX_SOCKETS, some commands are
skipped from the build. It does not make sense to list them in the
output of `git help -a`, so let's just not.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -611,6 +611,7 @@ FUZZ_PROGRAMS =
 LIB_OBJS =
 PROGRAM_OBJS =
 PROGRAMS =
+EXCLUDED_PROGRAMS =
 SCRIPT_PERL =
 SCRIPT_PYTHON =
 SCRIPT_SH =
@@ -1319,6 +1320,7 @@ ifdef NO_CURL
 	REMOTE_CURL_PRIMARY =
 	REMOTE_CURL_ALIASES =
 	REMOTE_CURL_NAMES =
+	EXCLUDED_PROGRAMS += git-http-fetch git-http-push
 else
 	ifdef CURLDIR
 		# Try "-Wl,-rpath=$(CURLDIR)/$(lib)" in such a case.
@@ -1343,7 +1345,11 @@ endif
 	ifeq "$(curl_check)" "070908"
 		ifndef NO_EXPAT
 			PROGRAM_OBJS += http-push.o
+		else
+			EXCLUDED_PROGRAMS += git-http-push
 		endif
+	else
+		EXCLUDED_PROGRAMS += git-http-push
 	endif
 	curl_check := $(shell (echo 072200; $(CURL_CONFIG) --vernum | sed -e '/^70[BC]/s/^/0/') 2>/dev/null | sort -r | sed -ne 2p)
 	ifeq "$(curl_check)" "072200"
@@ -1589,7 +1595,9 @@ ifdef NO_INET_PTON
 	LIB_OBJS += compat/inet_pton.o
 	BASIC_CFLAGS += -DNO_INET_PTON
 endif
-ifndef NO_UNIX_SOCKETS
+ifdef NO_UNIX_SOCKETS
+	EXCLUDED_PROGRAMS += git-credential-cache git-credential-cache--daemon
+else
 	LIB_OBJS += unix-socket.o
 	PROGRAM_OBJS += credential-cache.o
 	PROGRAM_OBJS += credential-cache--daemon.o
@@ -2108,7 +2116,9 @@ $(BUILT_INS): git$X
 command-list.h: generate-cmdlist.sh command-list.txt
 
 command-list.h: $(wildcard Documentation/git*.txt) Documentation/*config.txt Documentation/config/*.txt
-	$(QUIET_GEN)$(SHELL_PATH) ./generate-cmdlist.sh command-list.txt >$@+ && mv $@+ $@
+	$(QUIET_GEN)$(SHELL_PATH) ./generate-cmdlist.sh \
+		$(patsubst %,--exclude-program %,$(EXCLUDED_PROGRAMS)) \
+		command-list.txt >$@+ && mv $@+ $@
 
 SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):$(GIT_VERSION):\
 	$(localedir_SQ):$(NO_CURL):$(USE_GETTEXT_SCHEME):$(SANE_TOOL_PATH_SQ):\

generate-cmdlist.sh

@@ -6,7 +6,7 @@ die () {
 }
 
 command_list () {
-	grep -v '^#' "$1"
+	eval "grep -ve '^#' $exclude_programs" <"$1"
 }
 
 get_categories () {
@@ -93,6 +93,14 @@ EOF
 EOF
 }
 
+exclude_programs=
+while test "--exclude-program" = "$1"
+do
+	shift
+	exclude_programs="$exclude_programs -e \"^$1 \""
+	shift
+done
+
 echo "/* Automatically generated by generate-cmdlist.sh */
 struct cmdname_help {
 	const char *name;