Build both stages of curl in sysc

The source tarball is provided as part of sysa distfiles and copied to sysc, which resolves the issue of finding a reliable plain HTTP mirror for curl.

Splitted from https://github.com/fosslinux/live-bootstrap/pull/253.

sysc/run.sh

@@ -36,6 +36,14 @@ create_fhs
 
 populate_device_nodes
 
+if [ -e "${SOURCES}/distfiles" ]; then
+    mv "${SOURCES}/distfiles" /
+else
+    mkdir -p "${DISTFILES}"
+fi
+
+build curl-7.88.1 pass1.sh
+
 # Obtain network connection
 if [ "${CHROOT}" = "False" ]; then
     dhcpcd --waitip=4
@@ -52,12 +60,6 @@ if [ "${CHROOT}" = "False" ]; then
     done
 fi
 
-if [ -e "${SOURCES}/distfiles" ]; then
-    mv "${SOURCES}/distfiles" /
-else
-    mkdir -p "${DISTFILES}"
-fi
-
 build bash-5.2.15
 
 exec env -i PATH="${PATH}" HOME="${HOME}" SOURCE_DATE_EPOCH="${SOURCE_DATE_EPOCH}" bash run2.sh