Add dwarf flavour definition

mk/flavours/dwarf.mk

+# Build flavour which produces a compiler, RTS, and core libraries with DWARF
+# debug information. For best results run ./configure with
+# --enable-dwarf-unwind.
+
+SRC_HC_OPTS        = -O -H64m
+GhcStage1HcOpts    = -O2
+GhcStage2HcOpts    = -O2 -g3
+GhcRtsHcOpts       = -O2 -g3
+GhcLibHcOpts       = -O2 -g3
+BUILD_PROF_LIBS    = YES
+#SplitObjs
+#HADDOCK_DOCS
+#BUILD_SPHINX_HTML
+#BUILD_SPHINX_PDF