diff --git a/aegisub/Makefile.am b/aegisub/Makefile.am
index 10276c114..831708062 100644
--- a/aegisub/Makefile.am
+++ b/aegisub/Makefile.am
@@ -4,13 +4,14 @@ noinst_LIBRARIES=
 
 SUBDIRS = bitmaps posix
 
-AM_CPPFLAGS = -DAEGISUB -Iposix -include posix/defines.h @WX_CPPFLAGS@
+AM_CXXFLAGS = -DAEGISUB -Iposix -include posix/defines.h @WX_CPPFLAGS@
 
 bin_PROGRAMS = aegisub
 aegisub_LDADD = posix/libposix.a
-aegisub_CPPFLAGS = @FREETYPE_CFLAGS@ -DAEGISUB -Iposix -include posix/defines.h @WX_CPPFLAGS@
+aegisub_CPPFLAGS = @FREETYPE_CFLAGS@
 aegisub_LDFLAGS = @GL_LIBS@ @FREETYPE_LIBS@ @PTHREAD_LIBS@ @WX_LIBS@
 
+
 #XXX: fix this so it's generated by configure and put into acconf.h
 #BUILDINFO := -DBUILD_CREDIT=verm -DBUILD_SVN_REVISION=0