This patch arranges so that we don't end up, with profiling builds, with a
file named `<stdout>.gcov' since that confuses lcov:

  <stdout>:cannot open source file
  geninfo: ERROR: cannot read <stdout>.gcov!

--- guile/libguile/c-tokenize.c	2009-09-13 13:05:15.000000000 +0200
+++ guile/libguile/c-tokenize.c	2009-10-28 16:24:15.000000000 +0100
@@ -1,5 +1,5 @@
 
-#line 3 "<stdout>"
+#line 3 "c-tokenize.c"
 
 #define  YY_INT_ALIGNED short int
 
@@ -616,7 +616,7 @@ int cookie_was_last = 0; 
 #define IS_COOKIE cookie_was_last = 1
 #define IS_NOT_COOKIE cookie_was_last = 0
  
-#line 620 "<stdout>"
+#line 620 "c-tokenize.c"
 
 #define INITIAL 0
 
@@ -799,7 +799,7 @@ YY_DECL
 #line 65 "./c-tokenize.lex"
 
 
-#line 803 "<stdout>"
+#line 803 "c-tokenize.c"
 
 	if ( !(yy_init) )
 		{
@@ -1235,7 +1235,7 @@ YY_RULE_SETUP
 #line 181 "./c-tokenize.lex"
 ECHO;
 	YY_BREAK
-#line 1239 "<stdout>"
+#line 1239 "c-tokenize.c"
 case YY_STATE_EOF(INITIAL):
 	yyterminate();