guile: Add as_a_scm_t_subr

Building GDB in C++ mode on Fedora 20, the gdb/guile/ code shows ~280
errors like:

 src/gdb/guile/guile.c:515:1: error: invalid conversion from ‘scm_unused_struct* (*)(SCM, SCM) {aka scm_unused_struct* (*)(scm_unused_struct*, scm_unused_struct*)}’ to ‘scm_t_subr {aka void*}’ [-fpermissive]

This commit fixes them all.

gdb/ChangeLog:
2015-09-07  Pedro Alves  <palves@redhat.com>

	* guile/guile-internal.h (as_a_scm_t_subr): New.
	* guile/guile.c (misc_guile_functions): Use it.
	* guile/scm-arch.c (arch_functions): Use it.
	* guile/scm-block.c (block_functions, gdbscm_initialize_blocks):
	Use it.
	* guile/scm-breakpoint.c (breakpoint_functions): Use it.
	* guile/scm-cmd.c (command_functions): Use it.
	* guile/scm-disasm.c (disasm_functions): Use it.
	* guile/scm-exception.c (exception_functions)
	(private_exception_functions): Use it.
	* guile/scm-frame.c (frame_functions)
	* guile/scm-gsmob.c (gsmob_functions): Use it.
	* guile/scm-iterator.c (iterator_functions): Use it.
	* guile/scm-lazy-string.c (lazy_string_functions): Use it.
	* guile/scm-math.c (math_functions): Use it.
	* guile/scm-objfile.c (objfile_functions): Use it.
	* guile/scm-param.c (parameter_functions): Use it.
	* guile/scm-ports.c (port_functions, private_port_functions): Use
	it.
	* guile/scm-pretty-print.c (pretty_printer_functions): Use it.
	* guile/scm-progspace.c (pspace_functions): Use it.
	* guile/scm-string.c (string_functions): Use it.
	* guile/scm-symbol.c (symbol_functions): Use it.
	* guile/scm-symtab.c (symtab_functions): Use it.
	* guile/scm-type.c (type_functions, gdbscm_initialize_types): Use
	it.
	* guile/scm-value.c (value_functions): Use it.

1 files changed, 7 insertions, 5 deletions

diff --git a/gdb/guile/scm-param.c b/gdb/guile/scm-param.c
index 3ddd98f..d216aad 100644
--- a/gdb/guile/scm-param.c
+++ b/gdb/guile/scm-param.c
@@ -1117,7 +1117,7 @@ gdbscm_set_parameter_value_x (SCM self, SCM value)
 
 static const scheme_function parameter_functions[] =
 {
-  { "make-parameter", 1, 0, 1, gdbscm_make_parameter,
+  { "make-parameter", 1, 0, 1, as_a_scm_t_subr (gdbscm_make_parameter),
     "\
 Make a GDB parameter object.\n\
 \n\
@@ -1149,20 +1149,22 @@ Make a GDB parameter object.\n\
     show-doc: The \"doc string\" when showing the parameter.\n\
     initial-value: The initial value of the parameter." },
 
-  { "register-parameter!", 1, 0, 0, gdbscm_register_parameter_x,
+  { "register-parameter!", 1, 0, 0,
+    as_a_scm_t_subr (gdbscm_register_parameter_x),
     "\
 Register a <gdb:parameter> object with GDB." },
 
-  { "parameter?", 1, 0, 0, gdbscm_parameter_p,
+  { "parameter?", 1, 0, 0, as_a_scm_t_subr (gdbscm_parameter_p),
     "\
 Return #t if the object is a <gdb:parameter> object." },
 
-  { "parameter-value", 1, 0, 0, gdbscm_parameter_value,
+  { "parameter-value", 1, 0, 0, as_a_scm_t_subr (gdbscm_parameter_value),
     "\
 Return the value of a <gdb:parameter> object\n\
 or any gdb parameter if param is a string naming the parameter." },
 
-  { "set-parameter-value!", 2, 0, 0, gdbscm_set_parameter_value_x,
+  { "set-parameter-value!", 2, 0, 0,
+    as_a_scm_t_subr (gdbscm_set_parameter_value_x),
     "\
 Set the value of a <gdb:parameter> object.\n\
 \n\