Allow overriding the bc implementation used in run-bc

While base bc is great, it uses libcrypto's BIGNUM implementation.
This implies that the independent verification of the bn_test isn't
as independent as it should be.

With this commit, run-bc picks up bn-gh if it is installed. This appears
to work on amd64, arm64 and sparc64 (where gbc is busted). I will send
PRs to the regress maintainers once I will have tested this a bit more
thoroughly. Committing this early since I juggle way too many diffs
already.

diff --git a/regress/lib/libcrypto/bn/Makefile b/regress/lib/libcrypto/bn/Makefile
index 2ba1d39..9d9d77a 100644 (file)
--- a/regress/lib/libcrypto/bn/Makefile
+++ b/regress/lib/libcrypto/bn/Makefile
@@ -1,4 +1,4 @@
-#      $OpenBSD: Makefile,v 1.30 2023/04/17 19:37:18 tb Exp $
+#      $OpenBSD: Makefile,v 1.31 2023/04/17 19:51:05 tb Exp $
 
 PROGS +=       bn_add_sub
 PROGS +=       bn_cmp
@@ -53,10 +53,15 @@ CLEANFILES += bn_isqrt_gen_tables.txt.tmp bn_isqrt_gen_tables.txt
 run-regress-bn_test bn_test.out: bn_test
        ./bn_test -out bn_test.out
 
+.if exists(/usr/local/bin/bc-gh)
+BC ?=  bc-gh
+.endif
+BC ?=  bc
+
 REGRESS_TARGETS +=     run-bc
 .PHONY:                run-bc
 run-bc: bn_test.out
-       bc < $> | tee bc.out | grep -v '^0$$'
+       ${BC} < $> | tee bc.out | grep -v '^0$$'
        ! grep -v '^test ' <bc.out | grep -v '^0$$'
 
 CLEANFILES +=  bn_test.out bc.out