--- a/configure.ac
+++ b/configure.ac
@@ -53,6 +53,7 @@
 
 dnl Check for libraries
 dnl Add your macro calls to check required libraries, if you have any.
+PKG_CHECK_MODULES([FFI], [libffi])
 
 dnl Platform-dependent configuration.
 AC_ARG_ENABLE(objc, [  --enable-objc           turn on Objective-C support])
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -20,9 +20,10 @@
 GAUCHE_PACKAGE = @GAUCHE_PACKAGE@
 INSTALL        = @GAUCHE_INSTALL@
 
-CPPFLAGS       = -I./libffi/include -DGAUCHE_API_0_8_8 @CPPFLAGS@
+CPPFLAGS       = -DGAUCHE_API_0_8_8 @FFI_CFLAGS@ @CPPFLAGS@
+CFLAGS         = @CFLAGS@
 LDFLAGS        = @LDFLAGS@
-LIBS           = libffi/.libs/libffi.a @LIBS@
+LIBS           = @FFI_LIBS@ @LIBS@
 
 YACC           = @YACC@
 
@@ -38,7 +39,7 @@
 SCMFILES  = 
 HEADERS   = 
 
-TARGET    = libffi/.libs/libffi.a $(ARCHFILES)
+TARGET    = $(ARCHFILES)
 GENERATED = libffi
 CONFIG_GENERATED = libffi/Makefile Makefile cwcompile
 
@@ -62,13 +63,13 @@
 	cd libffi; $(MAKE)
 
 c-ffi.$(SOEXT): $(ffi_SRCS)
-	$(GAUCHE_PACKAGE) compile --cppflags="$(CPPFLAGS)" --ldflags="$(LDFLAGS)" --libs="$(LIBS)" --verbose c-ffi $(ffi_SRCS)
+	$(GAUCHE_PACKAGE) compile --cppflags="$(CPPFLAGS)" --cflags="$(CFLAGS)" --ldflags="$(LDFLAGS)" --libs="$(LIBS)" --verbose c-ffi $(ffi_SRCS)
 
 c-lex.$(SOEXT): $(clex_SRCS)
-	$(GAUCHE_PACKAGE) compile --cppflags="$(CPPFLAGS)" --ldflags="$(LDFLAGS)" --libs="$(LIBS)" --verbose c-lex $(clex_SRCS)
+	$(GAUCHE_PACKAGE) compile --cppflags="$(CPPFLAGS)" --cflags="$(CFLAGS)" --ldflags="$(LDFLAGS)" --libs="$(LIBS)" --verbose c-lex $(clex_SRCS)
 
 c-parser.$(SOEXT): $(cparser_SRCS) y.tab.c
-	$(GAUCHE_PACKAGE) compile --cppflags="$(CPPFLAGS)" --ldflags="$(LDFLAGS)" --libs="$(LIBS) $(cparser_LIBS)" --verbose c-parser $(cparser_SRCS)
+	$(GAUCHE_PACKAGE) compile --cppflags="$(CPPFLAGS)" --cflags="$(CFLAGS)" --ldflags="$(LDFLAGS)" --libs="$(LIBS) $(cparser_LIBS)" --verbose c-parser $(cparser_SRCS)
 
 c-grammar.y: c-grammar.scm genyacc.scm
 	$(GOSH) genyacc.scm --outfile=c-grammar.y $<