version: greatly simplify redo nonsense, now that we use VERSION.

Signed-off-by: David Anderson <danderson@tailscale.com>

version/version.h.do

@@ -1,17 +1,9 @@
-redo-ifchange long.txt short.txt
-read -r long <long.txt
-read -r short <short.txt
+redo-ifchange version-info.sh
 
-# get it into "major.minor.patch" format
-ver=$(echo "$ver" | sed -e 's/-/./')
+. ./version-info.sh
 
-# winres is the MAJOR,MINOR,BUILD,REVISION 4-tuple used to identify
-# the version of Windows binaries. We always set REVISION to 0, which
-# seems to be how you map SemVer.
-winres=$(echo "$short,0" | sed -e 's/\./,/g')
-
-(
-	printf '#define TAILSCALE_VERSION_LONG "%s"\n' "$long"
-	printf '#define TAILSCALE_VERSION_SHORT "%s"\n' "$short"
-	printf '#define TAILSCALE_VERSION_WIN_RES %s\n' "$winres"
-) >$3
+cat >$3 <<EOF
+#define TAILSCALE_VERSION_LONG "$VERSION_LONG"
+#define TAILSCALE_VERSION_SHORT "$VERSION_SHORT"
+#define TAILSCALE_VERSION_WIN_RES $VERSION_WINRES
+EOF