Build with various extra warning options.

diff --git a/makefile b/makefile
--- a/makefile
+++ b/makefile
@@ -18,6 +18,10 @@ MENUDIR = $(PREFIX)/share/applications
 MENUDIR = $(PREFIX)/share/applications
 LOCALEDIR = $(PREFIX)/share/locale/
 
+CXXFLAGS = $(CFLAGS)
+CXXFLAGS += -Wformat=2 -Wformat-security -Wstrict-aliasing=2
+CXXFLAGS += -Wmissing-format-attribute -Wmissing-noreturn
+CXXFLAGS += -Wdisabled-optimization
 CXXFLAGS += `sdl-config --cflags` -DVERSION=$(VERSION) -DRELEASE=$(RELEASE) -DUSEPAK=$(USEPAK) -DDEV=$(DEV)
 CXXFLAGS += -DPAKNAME=\"$(PAKNAME)\" -DPAKLOCATION=\"$(DATADIR)\" -DGAMEPLAYMANUAL=\"$(DOCDIR)/index.html\" -Wall -pedantic
 CXXFLAGS += -DLOCALEDIR=\"$(LOCALEDIR)\"