move vars generation to its script

Makefile

@@ -141,7 +141,7 @@ version.inc.tex: Makefile $(shell git rev-parse --git-dir 2>/dev/null)
 	TZ=UTC date '+\gdef\VCDescribe{%F ($(REF))}%' > $@
 
 vars.inc.tex: vars.awk wm.sql Makefile
-	./$< wm.sql > $@
+	awk -f $< wm.sql
 
 slides-2021-03-29.pdf: slides-2021-03-29.txt
 	pandoc -t beamer -i $< -o $@

vars.awk

@@ -1,20 +1,19 @@
 #!/usr/bin/awk -f
 
-BEGIN {
-  FS="[() ]"
-}
+BEGIN { FS="[() ]" }
 
 /small_angle constant real default radians/ {
   if(d) {
     exit 1
   } else {
-    printf ("\\newcommand{\\smallAngle}{\\frac{\\pi}{%d}}\n",180/$8);
-    d=1
+    d = sprintf("\\newcommand{\\smallAngle}{\\frac{\\pi}{%d}}\n",180/$8);
   }
 }
 
 END{
-  if(!d){
+  if(d) {
+    print d > "vars.inc.tex"
+  } else {
     exit 1
   }
 }