Add -target js, current-compilation-target, compilation-target?`

src/gerbil/compiler/driver.ss

@@ -10,9 +10,7 @@ namespace: gxc
         "base"
         "compile"
         "optimize")
-(export compile-module compile-exe
-	current-compilation-target
-	compilation-target?)
+(export compile-module compile-exe)
 
 (extern namespace: #f gerbil-path) ;; needed until bootstrap re-generated
 
@@ -21,9 +19,6 @@ namespace: gxc
 (def default-gerbil-gcc "gcc")
 (def default-gerbil-ar "ar")
 
-(def current-compilation-target (make-parameter #f))
-(defrule (compilation-target? sym) (eq? (current-compilation-target) 'sym))
-
 (def +driver-mutex+ (make-mutex 'compiler/driver))
 (defrules with-driver-mutex ()
   ((_ expr)

src/gerbil/core/expander.ss

@@ -41,6 +41,7 @@ package: gerbil/core
     current-expander-path
     current-expander-phi
     current-expander-compiling?
+    current-compilation-target?
     current-module-reader-path
     current-module-reader-args
     local-context? top-context? module-context? prelude-context?

src/gerbil/core/sugar.ss

@@ -146,7 +146,10 @@ package: gerbil/core
       ((_ message detail ...)
        (stx-string? #'message)
        (apply raise-syntax-error #f (stx-e #'message) stx
-              (syntax->list #'(detail ...)))))))
+              (syntax->list #'(detail ...))))))
+
+  (defrules compilation-target? ()
+    ((_ sym) (eq? (gx#current-compilation-target) 'sym))))
 
 (module Sugar-2
   (import Sugar-1 (phi: +1 Sugar-1))

src/gerbil/expander/core.ss

@@ -37,6 +37,9 @@ namespace: gx
 (def current-expander-compiling?
   (make-parameter #f))
 
+(def current-compilation-target
+  (make-parameter #f))
+
 ;; expander context
 (defstruct expander-context (id table)
   constructor: :init!