gdb: Remove some C compiler support leftovers

Remove some __cplusplus checks, inline EXPORTED_CONST, and update some comments.

gdb/ChangeLog:
2016-10-06  Pedro Alves  <palves@redhat.com>

	* cp-valprint.c (vtbl_ptr_name): Write "extern const" instead of
	EXPORTED_CONST.
	* stub-termcap.c: Remove __cplusplus checks.
	* common/common-defs.h [!__cplusplus] (EXTERN_C, EXTERN_C_PUSH,
	EXTERN_C_POP): Delete.
	* common/common-exceptions.h (GDB_XCPT_SJMP): Update comments.
	(GDB_XCPT) [!__cplusplus]: Delete.
	(throw_exception, throw_exception_sjlj): Update comments.
	* guile/guile-internal.h (as_a_scm_t_subr) [!__cplusplus]: Delete.
	* guile/guile.c (extension_language_guile): Write "extern const"
	instead of EXPORTED_CONST.
	* features/feature_to_c.sh: Don't emit !__cplusplus code.  Write
	"extern const" instead of EXPORTED_CONST.

1 files changed, 8 insertions, 15 deletions

diff --git a/gdb/common/common-exceptions.h b/gdb/common/common-exceptions.h
index 6bf7e40..4cc56b4 100644
--- a/gdb/common/common-exceptions.h
+++ b/gdb/common/common-exceptions.h
@@ -119,8 +119,7 @@ struct gdb_exception
 
 /* The different exception mechanisms that TRY/CATCH can map to.  */
 
-/* Make GDB exceptions use setjmp/longjmp behind the scenes.  This is
-   the only mode supported when GDB is built as a C program.  */
+/* Make GDB exceptions use setjmp/longjmp behind the scenes.  */
 #define GDB_XCPT_SJMP 1
 
 /* Make GDB exceptions use try/catch behind the scenes.  */
@@ -132,11 +131,7 @@ struct gdb_exception
    spurious code between the TRY and the CATCH block.  */
 #define GDB_XCPT_RAW_TRY 3
 
-#ifdef __cplusplus
-# define GDB_XCPT GDB_XCPT_TRY
-#else
-# define GDB_XCPT GDB_XCPT_SJMP
-#endif
+#define GDB_XCPT GDB_XCPT_TRY
 
 /* Functions to drive the sjlj-based exceptions state machine.  Though
    declared here by necessity, these functions should be considered
@@ -305,18 +300,16 @@ struct gdb_quit_bad_alloc
 
 /* *INDENT-ON* */
 
-/* Throw an exception (as described by "struct gdb_exception").  When
-   GDB is built as a C program, executes a LONG JUMP to the inner most
-   containing exception handler established using TRY/CATCH.  When
-   built as a C++ program, throws a C++ exception, using "throw".  */
+/* Throw an exception (as described by "struct gdb_exception"),
+   landing in the inner most containing exception handler established
+   using TRY/CATCH.  */
 extern void throw_exception (struct gdb_exception exception)
      ATTRIBUTE_NORETURN;
 
 /* Throw an exception by executing a LONG JUMP to the inner most
-   containing exception handler established using TRY_SJLJ.  Works the
-   same regardless of whether GDB is built as a C program or a C++
-   program.  Necessary in some cases where we need to throw GDB
-   exceptions across third-party library code (e.g., readline).  */
+   containing exception handler established using TRY_SJLJ.  Necessary
+   in some cases where we need to throw GDB exceptions across
+   third-party library code (e.g., readline).  */
 extern void throw_exception_sjlj (struct gdb_exception exception)
      ATTRIBUTE_NORETURN;