BR3028880: Revert to nonfatal, better error message, cleanup

Revert to issuing a nonfatal error (it makes no sense to make it a
fatal error, but it probably makes sense for it to be an error instead
of a warning, especially since a lot of prior versions would crash and
apparently noone noticed.)  We might have to revisit this based on
user requirements, and/or provide a method for the user to detect an
existing environment variable (%ifenv?).

Issue a better error message, indicating the nature of the failure.

Simplify the code by just updating the string in "p".

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/preproc.c b/preproc.c
index 570f9d11..cc5034f3 100644
--- a/preproc.c
+++ b/preproc.c
@@ -1182,10 +1182,12 @@ static char *detoken(Token * tlist, bool expand_locals)
         if (t->type == TOK_PREPROC_ID && t->text[1] == '!') {
             char *p = getenv(t->text + 2);
             char *q = t->text;
-            if (p)
-                t->text = nasm_strdup(p);
-            else
-                error(ERR_FATAL, "`%s' is empty", q + 2);
+	    if (!p) {
+                error(ERR_NONFATAL | ERR_PASS1,
+		      "nonexistent environment variable `%s'", q + 2);
+		p = "";
+	    }
+	    t->text = nasm_strdup(p);
             nasm_free(q);
         }
         /* Expand local macros here and not during preprocessing */