[RFA 03/42] Add assert in prepare_for_building

[Tom Tromey]

This adds an assertion in prepare_for_building.  This was useful for
verifying whether some subsequent changes were valid.

gdb/ChangeLog
2018-05-22  Tom Tromey  <tom@tromey.com>

	* buildsym.c (prepare_for_building): Add assert.
---
 gdb/ChangeLog  | 4 ++++
 gdb/buildsym.c | 1 +
 2 files changed, 5 insertions(+)

diff --git a/gdb/buildsym.c b/gdb/buildsym.c
index b747a082b5..9e0c39a4a4 100644
--- a/gdb/buildsym.c
+++ b/gdb/buildsym.c
@@ -1025,6 +1025,7 @@ prepare_for_building (const char *name, CORE_ADDR start_addr)
   gdb_assert (pending_macros == NULL);
   gdb_assert (pending_addrmap == NULL);
   gdb_assert (current_subfile == NULL);
+  gdb_assert (buildsym_compunit == nullptr);
 }
 
 /* Start a new symtab for a new source file in OBJFILE.  Called, for example,
-- 
2.13.6