- Enhance .POSIX to set -e when invoking shells, as demanded by a

backward-incompatible change in the 2008 POSIX specification.
- Add the .SHELLFLAGS variable so people can choose their own shell flags.
- Add tests for this.
- Add documentation for this.

tests/scripts/targets/POSIX

@@ -0,0 +1,26 @@
+#                                                                    -*-perl-*-
+
+$description = "Test the behaviour of the .PHONY target.";
+
+$details = "";
+
+
+# Ensure turning on .POSIX enables the -e flag for the shell
+
+run_make_test(q!
+.POSIX:
+all: ; @false; true
+!,
+              '', "#MAKE#: *** [all] Error 1\n", 512);
+
+# User settings must override .POSIX
+
+run_make_test(q!
+.SHELLFLAGS = -xc
+.POSIX:
+all: ; @false; true
+!,
+              '', "+ false\n+ true\n");
+
+# This tells the test driver that the perl test script executed properly.
+1;

tests/scripts/variables/SHELL

@@ -56,4 +56,18 @@ two: export SHELL := /./$mshell\n".'
 one two:;@echo "$@: $(SHELL) $$SHELL"
 ', '', "two: /./$mshell /./$mshell\none: /././$mshell $mshell\n");
 
+# Test .SHELLFLAGS
+
+run_make_test(q!
+.SHELLFLAGS = -xc
+all: ; @true
+!,
+              '', "+ true\n");
+
+run_make_test(q!
+.SHELLFLAGS = -xec
+all: ; @true; false; true
+!,
+              '', "+ true\n+ false\n#MAKE#: *** [all] Error 1\n", 512);
+
 1;