log4cpp: fix autoreconf

autoreconf needs to be told where to find macros as the Makefile.am does
not do this.

Signed-off-by: Ross Burton <ross.burton@arm.com>

meta-oe/recipes-support/log4cpp/log4cpp_1.1.4.bb

@@ -12,6 +12,8 @@ S = "${WORKDIR}/${BPN}"
 
 inherit autotools pkgconfig
 
+EXTRA_AUTORECONF += "-I m4"
+
 EXTRA_OECONF = "\
     --enable-doxygen=no \
     --enable-dot=no \