diff --git a/src/Makefile.am b/src/Makefile.am
index 9271201..9855666 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -25,7 +25,8 @@ noinst_HEADERS = asfont.h button.h cpu.h dirdialog.h FastDelegate.h \
 
 AM_CFLAGS= @CFLAGS@ @SDL_CFLAGS@
 
-AM_CXXFLAGS = @CXXFLAGS@ @SDL_CFLAGS@ -Isparsehash-1.6/src
+AM_CXXFLAGS = @CXXFLAGS@ @SDL_CFLAGS@ -Isparsehash-1.6/src -DTARGET_GP2X \
+	-Wall -Wextra -Wundef -Wunused-macros
 
 gmenu2x_LDADD = @LIBS@ @SDL_LIBS@ -lfreetype -lSDL_image -lSDL_ttf -lSDL_gfx -lSDL -ljpeg -lpng12 -lz -ldl -lpthread