Ensure variable_buffer is always set.

Initialize the global variable_buffer in main() so that it is never
a null pointer.  Then invoking variable_expand("") is never needed:
simply use the variable_buffer pointer when we want to restart the
variable buffer.  The main point of this simplification is not to
keep a separate pointer to the beginning of the buffer: this is
dangerous because the buffer may be re-allocated.  Instead always
use the variable_buffer pointer itself.

* src/variable.h (initialize_variable_output): Publish.
* src/expand.c (initialize_variable_output): Remove static.
* src/main.c (main): Initialize variable_buffer.
* src/file.c (enter_prereqs): Don't call variable_expand("") and
don't save a separate buffer pointer than might be outdated.
(expand_deps): Ditto.
* src/read.c (record_files): Ditto.
* src/remake.c (library_search): Ditto.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/variable.h b/src/variable.h
index 23f3282f..509777c4 100644
--- a/src/variable.h
+++ b/src/variable.h
@@ -129,6 +129,7 @@ char *allocated_variable_expand_for_file (const char *line, struct file *file);
   allocated_variable_expand_for_file (line, (struct file *) 0)
 char *expand_argument (const char *str, const char *end);
 char *variable_expand_string (char *line, const char *string, size_t length);
+char *initialize_variable_output ();
 void install_variable_buffer (char **bufp, size_t *lenp);
 void restore_variable_buffer (char *buf, size_t len);