Set .SHELLFLAGS to match Posix behaviour

Early failure upon the failure of a command seems like a good thing??

diff --git a/GNUmakefile b/GNUmakefile
index 84bbab84d73acf747bf3ce64464b29d4a47b8139..ba4df950d2927fbd25c997d39765a58b280ccdf5 100644 (file)
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -233,6 +233,12 @@ VERBOSE :=
 # The default target for this makefile.
 .DEFAULT_GOAL := all
 
+# Flags for use when calling the shell.
+#
+# `-e` enables early exit from invocations of multiple commands after
+# the first failure.
+.SHELLFLAGS := -c -e
+
 # ━ § BEGIN SHARED MAKE·FILE CONSTRUCTS ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
 
 # ─ ¶ Non‐Recipe Variable Definitions ─────────────────────────────────