diff -ur m4-1.4.13-orig/src/builtin.c m4-1.4.13/src/builtin.c
--- m4-1.4.13-orig/src/builtin.c	2009-03-05 12:46:01.000000000 +0000
+++ m4-1.4.13/src/builtin.c	2009-07-07 10:05:01.000000000 +0100
@@ -1486,19 +1486,39 @@
 static void
 m4___file__ (struct obstack *obs, int argc, token_data **argv)
 {
-  if (bad_argc (argv[0], argc, 1, 1))
+  if (bad_argc (argv[0], argc, 1, 2))
     return;
-  obstack_grow (obs, lquote.string, lquote.length);
-  obstack_grow (obs, current_file, strlen (current_file));
-  obstack_grow (obs, rquote.string, rquote.length);
+  if (*ARG (1)) 
+    {
+      isp->file = (char *) obstack_copy0 (&file_names, 
+					  ARG (1), strlen (ARG (1)));
+      output_current_line = -1;
+      input_change = 1;
+    }
+  else 
+    {
+      obstack_grow (obs, lquote.string, lquote.length);
+      obstack_grow (obs, current_file, strlen (current_file));
+      obstack_grow (obs, rquote.string, rquote.length);
+    }
 }
 
 static void
 m4___line__ (struct obstack *obs, int argc, token_data **argv)
 {
-  if (bad_argc (argv[0], argc, 1, 1))
+  int value;
+
+  if (bad_argc (argv[0], argc, 1, 2))
     return;
-  shipout_int (obs, current_line);
+  if (*ARG (1)) 
+    {
+      if (!numeric_arg (argv[0], ARG (1), &value))
+	return;
+      isp->line = value;
+      input_change = 1;
+    }
+  else 
+    shipout_int (obs, current_line);
 }
 
 static void
diff -ur m4-1.4.13-orig/src/input.c m4-1.4.13/src/input.c
--- m4-1.4.13-orig/src/input.c	2009-02-23 04:36:37.000000000 +0000
+++ m4-1.4.13/src/input.c	2009-07-07 09:59:26.000000000 +0100
@@ -64,44 +64,6 @@
 #include "regex.h"
 #endif
 
-enum input_type
-{
-  INPUT_STRING,		/* String resulting from macro expansion.  */
-  INPUT_FILE,		/* File from command line or include.  */
-  INPUT_MACRO		/* Builtin resulting from defn.  */
-};
-
-typedef enum input_type input_type;
-
-struct input_block
-{
-  struct input_block *prev;	/* previous input_block on the input stack */
-  input_type type;		/* see enum values */
-  const char *file;		/* file where this input is from */
-  int line;			/* line where this input is from */
-  union
-    {
-      struct
-	{
-	  char *string;		/* remaining string value */
-	  char *end;		/* terminating NUL of string */
-	}
-	u_s;	/* INPUT_STRING */
-      struct
-	{
-	  FILE *fp;		     /* input file handle */
-	  bool_bitfield end : 1;     /* true if peek has seen EOF */
-	  bool_bitfield close : 1;   /* true if we should close file on pop */
-	  bool_bitfield advance : 1; /* track previous start_of_input_line */
-	}
-	u_f;	/* INPUT_FILE */
-      builtin_func *func;	/* pointer to macro's function */
-    }
-  u;
-};
-
-typedef struct input_block input_block;
-
 
 /* Current input file name.  */
 const char *current_file;
@@ -113,7 +75,7 @@
 static struct obstack token_stack;
 
 /* Obstack for storing file names.  */
-static struct obstack file_names;
+struct obstack file_names;
 
 /* Wrapup input stack.  */
 static struct obstack *wrapup_stack;
@@ -125,7 +87,7 @@
 static void *token_bottom;
 
 /* Pointer to top of current_input.  */
-static input_block *isp;
+input_block *isp;
 
 /* Pointer to top of wrapup_stack.  */
 static input_block *wsp;
@@ -137,7 +99,7 @@
 static bool start_of_input_line;
 
 /* Flag for next_char () to recognize change in input block.  */
-static bool input_change;
+bool input_change;
 
 #define CHAR_EOF	256	/* character return on EOF */
 #define CHAR_MACRO	257	/* character return for MACRO token */
diff -ur m4-1.4.13-orig/src/m4.h m4-1.4.13/src/m4.h
--- m4-1.4.13-orig/src/m4.h	2008-12-12 13:11:39.000000000 +0000
+++ m4-1.4.13/src/m4.h	2009-07-07 09:59:02.000000000 +0100
@@ -481,3 +481,52 @@
 #else
 # define to_uchar(C) ((unsigned char) (C))
 #endif
+
+
+/* File: input.c -- input sources */  
+enum input_type
+{
+  INPUT_STRING,		/* String resulting from macro expansion.  */
+  INPUT_FILE,		/* File from command line or include.  */
+  INPUT_MACRO		/* Builtin resulting from defn.  */
+};
+
+typedef enum input_type input_type;
+
+struct input_block
+{
+  struct input_block *prev;	/* previous input_block on the input stack */
+  input_type type;		/* see enum values */
+  const char *file;		/* file where this input is from */
+  int line;			/* line where this input is from */
+  union
+    {
+      struct
+	{
+	  char *string;		/* remaining string value */
+	  char *end;		/* terminating NUL of string */
+	}
+	u_s;	/* INPUT_STRING */
+      struct
+	{
+	  FILE *fp;		     /* input file handle */
+	  bool_bitfield end : 1;     /* true if peek has seen EOF */
+	  bool_bitfield close : 1;   /* true if we should close file on pop */
+	  bool_bitfield advance : 1; /* track previous start_of_input_line */
+	}
+	u_f;	/* INPUT_FILE */
+      builtin_func *func;	/* pointer to macro's function */
+    }
+  u;
+};
+
+typedef struct input_block input_block;
+
+/* Pointer to top of current_input.  */
+extern input_block *isp;
+
+/* Flag for next_char () to recognize change in input block.  */
+extern bool input_change;
+
+/* Obstack for storing file names.  */
+extern struct obstack file_names;