Implement two new conditional operators `F <name>' and `S <name>'

which check whether <name> is a valid font or style, respectively.

* src/libs/libgroff/font.cpp (text_file): Add `silent' member.
(text_file::text_file): Updated.
(text_file::error): Don't emit message if `silent' is set.
(font::load_font): Add optional third argument (which is directly
passed to `load'.
(font::load): Add optional second argument to check the header of
a font only, without emitting warning or error messages.
* src/include/font.h (font): Updated.

* src/roff/troff/input.cpp (do_if_request): Implement `S' and `F'
conditionals.
* src/roff/troff/node.cpp (mount_font_no_translate): Add optional
fourth argument to check a font without mounting.
(check_font, check_style): New functions.
* src/roff/troff/node.h: Updated.

* man/groff_diff.man, man/groff.man, NEWS, doc/groff.texinfo:
Updated.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/include/font.h b/src/include/font.h
index 3d46138e..987cf6cc 100644
--- a/src/include/font.h
+++ b/src/include/font.h
@@ -57,7 +57,7 @@ public:
 
   static int scan_papersize(const char *, const char **, double *, double *);
 
-  static font *load_font(const char *, int *not_found = 0);
+  static font *load_font(const char *, int * = 0, int = 0);
   static void command_line_font_dir(const char *path);
   static FILE *open_file(const char *name, char **pathp);
   static int load_desc();
@@ -117,5 +117,5 @@ private:
 					   const char *file, int lineno);
 protected:
   font(const char *);
-  int load(int *not_found = 0);
+  int load(int * = 0, int = 0);
 };