[PATCH 3/3] tools/nolibc: add a help target to list supported targets

[Willy Tarreau <w@1wt.eu>]

The "help" target simply presents the list of supported targets
and the current set of variables being used to build the sysroot.

Since the help in tools/ suggests to use "install", which is
supported by most tools while such a target is not really relevant
here, an "install" target was also added, redirecting to "help".

Signed-off-by: Willy Tarreau <w@1wt.eu>
---
 tools/include/nolibc/Makefile | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index 9768819abd55..cfd06764b5ae 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -31,6 +31,23 @@ all_files := ctype.h errno.h nolibc.h signal.h std.h stdio.h stdlib.h string.h \
 # install all headers needed to support a bare-metal compiler
 all: headers
 
+install: help
+
+help:
+	@echo "Supported targets under nolibc:"
+	@echo "  all                 call \"headers\""
+	@echo "  clean               clean the sysroot"
+	@echo "  headers             prepare a sysroot in tools/include/nolibc/sysroot"
+	@echo "  headers_standalone  like \"headers\", and also install kernel headers"
+	@echo "  help                this help"
+	@echo ""
+	@echo "These targets may also be called from tools as \"make nolibc_<target>\"."
+	@echo ""
+	@echo "Currently using the following variables:"
+	@echo "  ARCH    = $(ARCH)"
+	@echo "  OUTPUT  = $(OUTPUT)"
+	@echo ""
+
 # Note: when ARCH is "x86" we concatenate both x86_64 and i386
 headers:
 	$(Q)mkdir -p $(OUTPUT)sysroot
-- 
2.17.5