libgc: Fix build

packages/libgc/build.sh

@@ -5,12 +5,17 @@ TERMUX_PKG_DESCRIPTION="Library providing the Boehm-Demers-Weiser conservative g
 # from 2016-0-114 21:34 for now.
 TERMUX_PKG_VERSION=7.4.201601142134
 TERMUX_PKG_SRCURL=https://github.com/ivmai/bdwgc/archive/c861ec3d1825b5bb450d20bf9091562fa8a81a4d.zip
-TERMUX_PKG_FOLDERNAME=bdwgc-master
+TERMUX_PKG_FOLDERNAME=bdwgc-c861ec3d1825b5bb450d20bf9091562fa8a81a4d
 TERMUX_PKG_RM_AFTER_INSTALL="share/gc"
 
 # Avoid defining structs already defined in api level 21 or beyond
 CFLAGS+=" -DGC_DONT_DEFINE_LINK_MAP"
 
+termux_step_pre_configure () {
+	cd $TERMUX_PKG_SRCDIR
+	autoconf
+}
+
 termux_step_post_extract_package () {
 	LIBATOMIC_VERSION=7.4.2
 	LIBATOMIC_FILE=libatomic_ops-${LIBATOMIC_VERSION}.tar.gz