diff --git a/config.mk b/config.mk
index dcc5bb3dc3..7747771cb2 100644
--- a/config.mk
+++ b/config.mk
@@ -20,13 +20,13 @@
 #MANPREFIX = ${PREFIX}/man
 
 # includes and libs
-INCS = -I$(X11INC) -I$(FREETYPEINC)
-LIBS = -L$(X11LIB) -lX11 $(XINERAMALIBS) $(FREETYPELIBS)
+INCS = $(X11INC) $(FREETYPEINC)
+LIBS = $(X11LIB) $(XINERAMALIBS) $(FREETYPELIBS)
 
 # flags
-CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700 -D_POSIX_C_SOURCE=200809L -DVERSION=\"$(VERSION)\" $(XINERAMAFLAGS)
-CFLAGS   = -std=c99 -pedantic -Wall -Os $(INCS) $(CPPFLAGS)
-LDFLAGS  = $(LIBS)
+CPPFLAGS += -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700 -D_POSIX_C_SOURCE=200809L -DVERSION=\"$(VERSION)\" $(XINERAMAFLAGS)
+CFLAGS   += -std=c99 -pedantic -Wall $(INCS) $(CPPFLAGS)
+LDFLAGS  += $(LIBS)
 
 # compiler and linker
 CC = cc