MVP build process

Doesn't push to the apt mirror yet, but it builds what I need to handle that step manually.

Closes #1

scripts/build.sh

 #!/usr/bin/env bash
 
+set -e
+set -x
+
 # Log when the build occurred.
 date
 echo ""
@@ -10,13 +13,16 @@ export OG_DIR
 echo "$OG_DIR"
 echo ""
 
-# Common directories.
+# Common paths.
 NGINX_SRC_DIR="$OG_DIR/src/nginx"
 export NGINX_SRC_DIR
 mkdir -p "$NGINX_SRC_DIR"
 
 NGINX_SRC_ARCHIVE="$OG_DIR/src/nginx-src.tar.gz"
-EXPORT NGINX_SRC_ARCHIVE
+export NGINX_SRC_ARCHIVE
+
+NGINX_SRC_ARCHIVE_SIGNATURE="$OG_DIR/src/nginx-src.tar.gz.asc"
+export NGINX_SRC_ARCHIVE_SIGNATURE
 
 OPENSSL_DIR="$OG_DIR/src/openssl"
 export OPENSSL_DIR
@@ -45,9 +51,16 @@ git clone -q --recursive --depth 1 https://github.com/grahamedgecombe/nginx-ct.g
 
 # Configure nginx
 echo ""
-echo "DOWNLOADING NGINX RELEASE"
+echo "DOWNLOADING & VERIFYING NGINX RELEASE"
 cd "$OG_DIR" || exit
+
 curl -o "$NGINX_SRC_ARCHIVE" "$NGINX_SRC"
+curl -o "$NGINX_SRC_ARCHIVE_SIGNATURE" "$NGINX_SIGNING"
+
+# Disabled as nginx is signing with individuals' keys.
+#gpg --import <(curl https://nginx.org/keys/nginx_signing.key)
+#gpg --verify "$NGINX_SRC_ARCHIVE_SIGNATURE" "$NGINX_SRC_ARCHIVE"
+
 tar -zxvf "$NGINX_SRC_ARCHIVE" -C "$NGINX_SRC_DIR" --strip 1
 cd "$NGINX_SRC_DIR" || exit
 ./configure \
@@ -94,5 +107,5 @@ cd "$NGINX_SRC_DIR" || exit
 echo ""
 echo "BUILDING NGINX"
 echo "Using $(nproc) jobs"
-make -j$(nproc)
+make -j"$(nproc)"
 "$NGINX_SRC_DIR/objs/nginx -V"