--- build.mak.in
+++ build.mak.in
@@ -284,6 +284,6 @@
 export PJ_INSTALL_DIR := @prefix@
 export PJ_INSTALL_INC_DIR := @includedir@
 export PJ_INSTALL_LIB_DIR := @libdir@
-export PJ_INSTALL_CFLAGS := -I$(PJ_INSTALL_INC_DIR) -DPJ_AUTOCONF=1	@CFLAGS@
+export PJ_INSTALL_CFLAGS := -DPJ_AUTOCONF=1 @CFLAGS@
 export PJ_INSTALL_CXXFLAGS := $(PJ_INSTALL_CFLAGS)
-export PJ_INSTALL_LDFLAGS := -L$(PJ_INSTALL_LIB_DIR) $(APP_LDLIBS)
+export PJ_INSTALL_LDFLAGS := $(APP_LDLIBS)