-$(curdir)/builddirs := sed sstrip ipkg-utils genext2fs squashfs mtd-utils lzma mkimage firmware-utils patch-cmdline pkg-config autoconf automake $(if $(CONFIG_CCACHE),ccache) bison $(if $(CONFIG_powerpc),dtc) quilt $(if $(CONFIG_GCC_VERSION_4_3),gmp mpfr) yaffs2
+$(curdir)/builddirs := sed sstrip ipkg-utils genext2fs squashfs mtd-utils lzma mkimage firmware-utils patch-cmdline pkg-config m4 autoconf automake $(if $(CONFIG_CCACHE),ccache) bison $(if $(CONFIG_powerpc),dtc) quilt $(if $(CONFIG_GCC_VERSION_4_3),gmp mpfr) yaffs2