sh: Don't require the setting of POSIXLY_CORRECT on Linux

README.md

@@ -53,7 +53,7 @@ You can also just run any command you want by passing it to `bob sh`, like so:
 
 ```console
 bob sh echo test
-bob sh sh -c "echo \$PATH"
+bob sh -- sh -c "echo \$PATH"
 ```
 
 The second command will print out the value of the `$PATH` environment variable, and it should be prepended by the `bin` directory of the temporary installation prefix.

src/bsys.c

@@ -174,6 +174,12 @@ int bsys_sh(bsys_t const* bsys, int argc, char* argv[]) {
 
 	else {
 		for (int i = 0; i < argc; i++) {
+			// On BSD/macOS, getopt doesn't consume the '--' argument.
+
+			if (strcmp(argv[i], "--") == 0) {
+				continue;
+			}
+
 			cmd_add(&cmd, argv[i]);
 		}
 	}

tests/sh.sh

@@ -11,7 +11,7 @@ if [ "$(bob sh echo test | tail -n1)" != "test" ]; then
 	exit 1
 fi
 
-if [ "$(bob sh sh -c "echo \$PATH" | tail -n1 | cut -d':' -f1)" != ".bob/prefix/bin" ]; then
+if [ "$(bob sh -- sh -c "echo \$PATH" | tail -n1 | cut -d':' -f1)" != ".bob/prefix/bin" ]; then
 	echo "Temporary installation prefix not in \$PATH." >&2
 	exit 1
 fi