Should use tmpfs for rustc-home to avoid git timeouts

Makefile

@@ -6,6 +6,7 @@ all: config-toml
 
 	tar xf rustc-1.47.0-src.tar.gz
 	mkdir rustc-home
+	mount -t tmpfs -o size=2G tmpfs rustc-home
 
 	if [ `uname -m` = "armv7l" ]; then \
 	    echo "$$CONFIG_TOML" | sed "s/TARGET/ARM/" > rustc-1.47.0-src/config.toml ; \
@@ -24,6 +25,7 @@ all: config-toml
 	    rm -rf /lib64 ; \
 	fi
 
+	umount rustc-home
 	rm -rf rustc-home
 	rm -rf rustc-1.47.0-src
 
@@ -38,6 +40,7 @@ temporary:
 
 	tar xf rustc-1.47.0-src.tar.gz
 	mkdir rustc-home
+	mount -t tmpfs -o size=2G tmpfs rustc-home
 
 	if [ `uname -m` = "armv7l" ]; then \
 	    echo "$$CONFIG_TOML" | sed "s/\/usr/\/build\/usr/" | sed "s/TARGET/ARM/" > rustc-1.47.0-src/config.toml ; \
@@ -64,15 +67,17 @@ temporary:
 	    rm -rf /lib64 ; \
 	fi
 
-	swapoff swap
-	rm -rf swap
-
 	echo "/build/usr/lib" >> /etc/ld.so.conf
 	ldconfig
 
 clean:
+	umount rustc-home
 	rm -rf rustc-home
 	rm -rf rustc-1.47.0-src
+
+	swapoff swap
+	rm -rf swap
+
 	rm -rf /build/usr
 	rm -f /etc/bash_completion.d/cargo
 	sed '/^\/build\/usr\/lib/d' -i /etc/ld.so.conf