Makefile: for convenience forward targets to GNUmake

Makefile

@@ -1,2 +1,42 @@
 all:
-	@echo please use GNU make, thanks!
+	@echo trying to use GNU make...
+	@gmake all
+
+source-only:
+	@gmake source-only
+
+binary-only:
+	@gmake binary-only
+
+distrib:
+	@gmake distrib
+
+man:
+	@gmake man
+
+install:
+	@gmake install
+
+document:
+	@gmake document
+
+deepclean:
+	@gmake deepclean
+
+code-format:
+	@gmake code-format
+
+help:
+	@gmake help
+
+tests:
+	@gmake tests
+
+unit:
+	@gmake unit
+
+unit_clean:
+	@gmake unit_clean
+
+clean:
+	@gmake clean