Import bmake-20200902vendor/NetBSD/bmake/20200902

Lots of code refactoring, simplification and cleanup.
Lots of new unit-tests providing much higher code coverage.
All courtesy of rillig at netbsd.

Other significant changes:

o new read-only variable .SHELL which provides the path of the shell
  used to run scripts (as defined by  the .SHELL target).

o new debug option -dl: LINT mode, does the equivalent of := for all
  variable assignments so that file and line number are reported for
  variable parse errors.

1 files changed, 24 insertions, 0 deletions

diff --git a/unit-tests/opt-keep-going.mk b/unit-tests/opt-keep-going.mk
new file mode 100644
index 000000000000..1a2124ccb5f1
--- /dev/null
+++ b/unit-tests/opt-keep-going.mk
@@ -0,0 +1,24 @@
+# $NetBSD: opt-keep-going.mk,v 1.3 2020/08/23 14:28:04 rillig Exp $
+#
+# Tests for the -k command line option, which stops building a target as soon
+# as an error is detected, but continues building the other, independent
+# targets, as far as possible.
+
+all: dependency other
+
+dependency:
+	@echo dependency 1
+	@false
+	@echo dependency 2
+	@:; exit 7
+	@echo dependency 3
+
+other:
+	@echo other 1
+	@false
+	@echo other 2
+
+all:
+	@echo main 1
+	@false
+	@echo main 2