Feature 2919629: Add help target for makefiles

CHANGES.txt

@@ -8,6 +8,7 @@
 - Feature 2839002: Add gcc switch to improve header dependency generation (Johannes Spohr)
 - Feature 2832906: Global variable (_SCRIPT) for current script path
 - Feature 2905303: Enable better folder matching in file lists
+- Feature 2919629: Add help target for makefiles
 - Bug 2909463: Fix Xcode handling of Obj-C++ .mm files
 - Bug 2903430: Using relative instead of absolute paths with $() macro
 - Bug 2910691: Duplicate build options

src/actions/make/make_solution.lua

@@ -12,15 +12,8 @@
 		local platforms = premake.filterplatforms(sln, cc.platforms, "Native")
 
 		-- write a header showing the build options
-		local cfgpairs = { }
-		for _, platform in ipairs(platforms) do
-			for _, cfgname in ipairs(sln.configurations) do
-				table.insert(cfgpairs, premake.getconfigname(cfgname, platform, true))
-			end
-		end
 		_p('# %s solution makefile autogenerated by Premake', premake.action.current().shortname)
-		_p('# Usage: make [ config=config_name ]')
-		_p('# Where {config_name} is one of: %s.', table.implode(cfgpairs, '"', '"', ', '))
+		_p('# Type "make help" for usage help')
 		_p('')
 		
 		-- set a default configuration
@@ -33,7 +26,7 @@
 		-- list the projects included in the solution
 		_p('PROJECTS := %s', table.concat(_MAKE.esc(table.extract(sln.projects, "name")), " "))
 		_p('')
-		_p('.PHONY: all clean $(PROJECTS)')
+		_p('.PHONY: all clean help $(PROJECTS)')
 		_p('')
 		_p('all: $(PROJECTS)')
 		_p('')
@@ -53,4 +46,29 @@
 		end
 		_p('')
 		
+		-- help rule
+		_p('help:')
+		_p(1,'@echo "Usage: make [config=name] [target]"')
+		_p(1,'@echo ""')
+		_p(1,'@echo "CONFIGURATIONS:"')
+
+		local cfgpairs = { }
+		for _, platform in ipairs(platforms) do
+			for _, cfgname in ipairs(sln.configurations) do
+				_p(1,'@echo "   %s"', premake.getconfigname(cfgname, platform, true))
+			end
+		end
+
+		_p(1,'@echo ""')
+		_p(1,'@echo "TARGETS:"')
+		_p(1,'@echo "   all (default)"')
+		_p(1,'@echo "   clean"')
+
+		for _, prj in ipairs(sln.projects) do
+			_p(1,'@echo "   %s"', prj.name)
+		end
+
+		_p(1,'@echo ""')
+		_p(1,'@echo "For more information, see http://industriousone.com/premake/quick-start"')
+		
 	end