diff --git a/aegisub/Makefile.am b/aegisub/Makefile.am
index a8f290265..d54c0bec0 100644
--- a/aegisub/Makefile.am
+++ b/aegisub/Makefile.am
@@ -12,7 +12,7 @@ aegisub_CPPFLAGS = @FREETYPE_CFLAGS@
 aegisub_LDFLAGS = @GL_LIBS@ @PTHREAD_LIBS@ @WX_LIBS@
 LIBS += @FREETYPE_LIBS@ @FONTCONFIG_LIBS@
 
-ifdef BUILD_DARWIN
+if BUILD_DARWIN
 aegisub_LDFLAGS += @AVUTIL_FFMPEG@
 endif