Reject obviously invalid DSA parameters during signing.

If g is zero, the retry loop will run infinitely. See
8f506274029903457c5f1d8663a012763f55cd37 from upstream.

Change-Id: I9e36002f2907dee3b5905e414e3c931d62b1a447
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/35924
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/dsa.h b/include/openssl/dsa.h
index bed93c5..8e3b9b3 100644
--- a/include/openssl/dsa.h
+++ b/include/openssl/dsa.h
@@ -436,5 +436,6 @@
 #define DSA_R_BAD_VERSION 104
 #define DSA_R_DECODE_ERROR 105
 #define DSA_R_ENCODE_ERROR 106
+#define DSA_R_INVALID_PARAMETERS 107
 
 #endif  // OPENSSL_HEADER_DSA_H