core: added new root Makefile

- forward make commands to src/ subfolder

Makefile

@@ -0,0 +1,18 @@
+#
+# Root Makefile for Kamailio project
+# - forward all commands to the Makefile in the src/ subfolder
+#
+
+# path to the source code folder
+KSR_DIR ?= src/
+
+# default target for makefile
+.DEFAULT_GOAL := default
+
+# forward all named targets
+%:
+	$(MAKE) -C $(KSR_DIR) "$@"
+
+# forward the default target
+default:
+	$(MAKE) -C $(KSR_DIR)