Explain the different build kinds

Author: CrazyPython

Makefile

@@ -1,11 +1,13 @@
 .PHONY = md2sexpr-build
 
+# Compile a debug build for quick development
 tree-query: tree-query.d interp.d query.d parser.d
 	dmd -g -debug -check=invariant -unittest tree-query.d interp.d query.d parser.d
 
 md2sexpr-build:
 	~/dlang/ldc-1.23.0/bin/ldc2 --link-defaultlib-shared=false -O3 -release md2sexpr.d parser.d
 
+# Compile with LLVM
 tree-query-build:
 	~/dlang/ldc-1.23.0/bin/ldc2 --link-defaultlib-shared=false -O2 -release tree-query.d interp.d query.d parser.d
 	strip tree-query