diff --git a/tools/Makefile b/tools/Makefile
index 5420360..3367834 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -18,14 +18,14 @@ INSTALL	= install
 all: $(TARGETS)
 
 panel-embed_OBJS = embed.o
-panel-embed_CFLAGS = $(CPPFLAGSF) $(CPPFLAGS) $(CFLAGSF) $(CFLAGS)
+panel-embed_CFLAGS = $(CPPFLAGSF) $(CPPFLAGS) -D PREFIX=\"$(PREFIX)\" $(CFLAGSF) $(CFLAGS)
 panel-embed_LDFLAGS = $(LDFLAGSF) $(LDFLAGS)
 
 panel-embed: $(panel-embed_OBJS)
 	$(CC) -o panel-embed $(panel-embed_OBJS) $(panel-embed_LDFLAGS)
 
 panel-message_OBJS = message.o
-panel-message_CFLAGS = $(CPPFLAGSF) $(CPPFLAGS) $(CFLAGSF) $(CFLAGS)
+panel-message_CFLAGS = $(CPPFLAGSF) $(CPPFLAGS) -D PREFIX=\"$(PREFIX)\" $(CFLAGSF) $(CFLAGS)
 panel-message_LDFLAGS = $(LDFLAGSF) $(LDFLAGS)
 
 panel-message: $(panel-message_OBJS)
diff --git a/tools/project.conf b/tools/project.conf
index 5c303d6..fc316a7 100644
--- a/tools/project.conf
+++ b/tools/project.conf
@@ -6,6 +6,7 @@ dist=Makefile,helper.c
 
 [panel-embed]
 type=binary
+cppflags=-D PREFIX=\"$(PREFIX)\"
 sources=embed.c
 install=$(BINDIR)
 
@@ -17,6 +18,7 @@ install=$(BINDIR)
 
 [panel-message]
 type=binary
+cppflags=-D PREFIX=\"$(PREFIX)\"
 sources=message.c
 install=$(BINDIR)