* tests/testsuite.at (AT_CHECK): When checking if $1 starts with

`bison ', use m4_index instead of m4_substr since chopping up a string
containing M4-special characters causes problems here.

Fix a couple of bugs related to special characters in user-specified
file names, and make it easier for skeletons to compute output file
names with the same file name prefix as Bison-computed output file
names.
* data/glr.cc, data/push.c, data/yacc.c: In @output, use
b4_parser_file_name and b4_spec_defines_file instead of
@output_parser_name@ and @output_header_name@, which are now redundant.
* data/glr.c, data/lalr1.cc: Likewise.  Also, in header #include's, use
b4_parser_file_name, b4_spec_defines_file, and the new
@basename(FILENAME@) instead of @output_parser_name@ and
@output_header_name@, which inappropriately escaped the file names as
C string literals.
* src/files.c (all_but_ext): Remove static qualifier.
(compute_output_file_names): Move `free (all_but_ext)' to...
(output_file_names_free): ... here since all_but_ext is needed later.
* src/files.h (all_but_ext): Extern.
* src/muscle_tab.h (MUSCLE_INSERT_STRING_RAW): New macro that does
exactly what MUSCLE_INSERT_STRING used to do.
(MUSCLE_INSERT_STRING): Use MUSCLE_OBSTACK_SGROW so that M4-special
characters are escaped properly.
* src/output.c (prepare): Define muscle file_name_all_but_ext as
all_but_ext.
For pkgdatadir muscle, maintain previous functionality by using
MUSCLE_INSERT_STRING_RAW instead of MUSCLE_INSERT_STRING.  The problem
is that b4_pkgdatadir is used inside m4_include in the skeletons, so
digraphs would never be expanded.  Hopefully no one has M4-special
characters in his Bison installation path.
* src/scan-skel.l: Don't parse @output_header_name@ and
@output_parser_name@ anymore since they're now redundant.
In @output, use decode_at_digraphs.
Parse a new @basename command that invokes last_component.
(decode_at_digraphs): New.
(BASE_QPUTS): Remove unused.
* tests/output.at (AT_CHECK_OUTPUT_FILE_NAME): New macro.
(Output file name): New tests.

data/glr.c

@@ -142,7 +142,7 @@ m4_define([b4_rhs_location],
 # We do want M4 expansion after # for CPP macros.
 m4_changecom()
 m4_divert(0)dnl
-@output @output_parser_name@
+@output b4_parser_file_name
 b4_copyright([Skeleton implementation for Bison GLR parsers in C],
   [2002, 2003, 2004, 2005, 2006])
 [
@@ -207,7 +207,7 @@ typedef struct YYLTYPE
 ]b4_user_provides])[]dnl
 ])
 
-b4_defines_if([#include @output_header_name@],
+b4_defines_if([[#include "@basename(]b4_spec_defines_file[@)"]],
 	      [b4_shared_declarations])[
 
 /* Enabling traces.  */
@@ -2629,7 +2629,7 @@ dnl glr.cc produces its own header.
 dnl
 m4_if(b4_skeleton, ["glr.c"],
 [b4_defines_if(
-[@output @output_header_name@
+[@output b4_spec_defines_file
 b4_copyright([Skeleton interface for Bison GLR parsers in C],
   [2002, 2003, 2004, 2005, 2006])
 

data/glr.cc

@@ -216,7 +216,7 @@ m4_defn([b4_parse_param])))],
 m4_include(b4_pkgdatadir/[glr.c])
 m4_popdef([b4_parse_param])
 
-@output @output_header_name@
+@output b4_spec_defines_file
 b4_copyright([Skeleton interface for Bison GLR parsers in C++],
   [2002, 2003, 2004, 2005, 2006])[
 

data/lalr1.cc

@@ -33,7 +33,7 @@ m4_include(b4_pkgdatadir/[location.cc])
 m4_changecom()
 m4_divert(0)dnl
 b4_defines_if(
-[@output @output_header_name@
+[@output b4_spec_defines_file
 b4_copyright([Skeleton interface for Bison LALR(1) parsers in C++],
   [2002, 2003, 2004, 2005, 2006])
 dnl FIXME: This is wrong, we want computed header guards.
@@ -301,7 +301,7 @@ m4_ifdef([b4_provides],
 
 [#endif /* ! defined PARSER_HEADER_H */]
 ])dnl
-@output @output_parser_name@
+@output b4_parser_file_name
 b4_copyright([Skeleton implementation for Bison LALR(1) parsers in C++],
   [2002, 2003, 2004, 2005, 2006])
 m4_if(b4_prefix, [yy], [],
@@ -312,8 +312,8 @@ m4_if(b4_prefix, [yy], [],
 /* First part of user declarations.  */
 ]b4_user_pre_prologue
 
-b4_defines_if([
-#include @output_header_name@])[
+b4_defines_if([[
+#include "@basename(]b4_spec_defines_file[@)"]])[
 
 /* User implementation prologue.  */
 ]b4_user_post_prologue[

data/push.c

@@ -134,7 +134,7 @@ m4_define([b4_rhs_location],
 # We do want M4 expansion after # for CPP macros.
 m4_changecom()
 m4_divert(0)dnl
-@output @output_parser_name@
+@output b4_parser_file_name
 b4_copyright([Skeleton implementation for Bison's Yacc-like parsers in C],dnl '
   [1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005, 2006])[
 
@@ -1638,7 +1638,7 @@ yyreturn:
 
 b4_epilogue
 b4_defines_if(
-[@output @output_header_name@
+[@output b4_spec_defines_file
 b4_copyright([Skeleton interface for Bison's Yacc-like parsers in C],dnl '
   [1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005, 2006])
 

data/yacc.c

@@ -134,7 +134,7 @@ m4_define([b4_rhs_location],
 # We do want M4 expansion after # for CPP macros.
 m4_changecom()
 m4_divert(0)dnl
-@output @output_parser_name@
+@output b4_parser_file_name
 b4_copyright([Skeleton implementation for Bison's Yacc-like parsers in C],dnl '
   [1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005, 2006])[
 
@@ -1485,7 +1485,7 @@ yyreturn:
 
 b4_epilogue
 b4_defines_if(
-[@output @output_header_name@
+[@output b4_spec_defines_file
 b4_copyright([Skeleton interface for Bison's Yacc-like parsers in C],dnl '
   [1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005, 2006])