diff --git a/lang/ninja/src/ninja.sld b/lang/ninja/src/ninja.sld
index 8164fe7..4ccb6de 100644
--- a/lang/ninja/src/ninja.sld
+++ b/lang/ninja/src/ninja.sld
@@ -217,7 +217,7 @@
         (try-resolve (build-rule-restat rule) #f)
         (try-resolve (build-rule-rspfile rule) #f)
         (try-resolve (build-rule-rspfile-content rule) #f)))
-  
+
    (define (bytevector-prefix? bv in-bv index)
      (define bv-len (bytevector-length bv))
      (define (inner-loop j)
@@ -229,9 +229,9 @@
      (if (> (+ index bv-len) (bytevector-length in-bv))
        #f
        (inner-loop 0)))
-  
+
    ;; Reads a full Ninja file, returning a <build-file> record.
-   (define (read-ninja-file strval)
+   (define (read-ninja-file-inner strval into read-other-file)
     (define i 0)
     (define (eat-whitespace)
       (cond
@@ -295,10 +295,11 @@
 
     (define (read-token)
      (define start-i i)
-     (define post-space (or (bytestring-index strval (lambda (ch) (not (= ch #x20))) i) i))
+     (define post-space-index (bytestring-index strval (lambda (ch) (not (= ch #x20))) i))
+     (define post-space (or post-space-index i))
      (define token
       (cond
-       ((>= i (bytevector-length strval))
+       ((>= post-space (bytevector-length strval))
         'eof)
        ((bytevector-prefix? #u8(#x23) strval post-space)
         (let ((end-of-comment (or (bytestring-index strval (lambda (ch) (= ch #x0A)) post-space) (bytevector-length strval))))
@@ -339,7 +340,9 @@
              ((string=? token "include") 'include)
              ((string=? token "subninja") 'subninja)
              (else token))))
-       (else #f)))
+       ((and (not post-space-index) (= (bytevector-u8-ref strval i) #x20))
+        'eof)
+       (else (fprintf (current-error-port) "found token ~S here\n" (number->string (bytevector-u8-ref strval i) 16)) #f)))
      (unless (member token '(newline eof #f)) (eat-whitespace))
      token)
     (define (expect-token expected)
@@ -445,17 +448,22 @@
         (let ((edge (read-build-edge file))) (set-build-file-build-edges! file (cons edge (build-file-build-edges file))))
         (read-toplevel file))
        ((default)
-        (do () ((expect-token 'newline)) (set-build-file-default-targets! file (cons (resolve-evalstring (read-eval-string-text #t) file #f #f #f) (build-file-default-targets file)))))
-       ((subninja include) (error "todo: includes"))
+        (do () ((expect-token 'newline)) (set-build-file-default-targets! file (cons (resolve-evalstring (read-eval-string-text #t) file #f #f #f) (build-file-default-targets file))))
+        (read-toplevel file))
+       ((include) (read-ninja-file-inner (read-other-file (resolve-evalstring (read-eval-string-text #t) file #f #f #f)) file read-other-file)
+        (read-toplevel file))
+       ((subninja) (error "todo: subninja"))
        ((pool) (read-pool) (read-toplevel file))
        ((newline) (read-toplevel file))
        (else
-         (unless (string? token) (error "unexpected" (list token i)))
+         (unless (string? token) (error "unexpected" (list token i (bytevector-length strval))))
          (unless (expect-token 'equals) (error "expected =, found" (read-token)))
          (let* ((value (read-eval-string-text #f)) (resolved (resolve-evalstring value file #f #f #f)))
            (set-build-file-global-variables! file (mapping-set! (build-file-global-variables file) token resolved)))
          (read-toplevel file)))
       file)
-    (define out-file (read-toplevel (make-build-file (mapping (make-default-comparator)) '() (mapping (make-default-comparator)) '() (mapping (make-default-comparator)))))
+    (read-toplevel into))
+   (define (read-ninja-file strval read-other-file)
+     (define out-file (read-ninja-file-inner strval (make-build-file (mapping (make-default-comparator)) '() (mapping (make-default-comparator)) '() (mapping (make-default-comparator))) read-other-file))
     (for-each (lambda (f) (unless (string=? (build-edge-rule f) "phony") (set-build-edge-resolved! f (build-rule-resolve (mapping-ref (build-file-rules out-file) (build-edge-rule f)) f out-file)))) (build-file-build-edges out-file))
     out-file)))
diff --git a/lang/ninja/src/nixpkgs.sld b/lang/ninja/src/nixpkgs.sld
index c8b29d0..f0ce4e6 100644
--- a/lang/ninja/src/nixpkgs.sld
+++ b/lang/ninja/src/nixpkgs.sld
@@ -101,10 +101,13 @@
 
     (set-ninja-build-config-root-dir! conf configured-vfs)
 
+    (define (read-file-at-path path)
+      (set! path (string-append "build/" path))
+      (define last-slash (string-contains-right path "/"))
+      (call-with-port (store-path-open (vfs-file-ref configured-vfs (string-copy path 0 last-slash) (string-copy path (+ 1 last-slash))))
+       (lambda (p) (read-bytevector (* 20 1024 1024) p))))
     (define ninja-file
-     (read-ninja-file
-      (call-with-port (store-path-open (vfs-file-ref configured-vfs "build" "build.ninja"))
-       (lambda (p) (read-bytevector (* 20 1024 1024) p)))))
+     (read-ninja-file (read-file-at-path "build.ninja") read-file-at-path))
 
     ; Process the build.ninja file.
     (define-values (edge-ref defaults) (process-ninja-file ninja-file conf "build"))