commit 0820ab24974cd2bad84c8ec5a90f7ce0e1681cf0
Author: Willy Tarreau <w@1wt.eu>
Date:   Wed Oct 3 09:40:22 2018 +0200

    BUILD: Makefile: add a "make opts" target to simply show the build options
    
    We're often missing an easy way to map input variables to output ones.
    The "opts" build target will simply show the input variables and the ones
    passed to the compiler and linker. This way it's easier to quickly see
    what a given build script or package will use, or the detected warnings
    supported by the compiler.
    
    (cherry picked from commit a8b12c6bb73b924f6429c3ae4d20b96992e92c2e)
    [wt: this is not needed but significantly helps for packaging]
    Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/Makefile b/Makefile
index 5d170041..d3615060 100644
--- a/Makefile
+++ b/Makefile
@@ -996,3 +996,20 @@ update-version:
 	echo "$(VERSION)" > VERSION
 	echo "$(SUBVERS)" > SUBVERS
 	echo "$(VERDATE)" > VERDATE
+
+# just display the build options
+opts:
+	@echo -n 'Using: '
+	@echo -n 'TARGET="$(strip $(TARGET))" '
+	@echo -n 'ARCH="$(strip $(ARCH))" '
+	@echo -n 'CPU="$(strip $(CPU))" '
+	@echo -n 'CC="$(strip $(CC))" '
+	@echo -n 'ARCH_FLAGS="$(strip $(ARCH_FLAGS))" '
+	@echo -n 'CPU_CFLAGS="$(strip $(CPU_CFLAGS))" '
+	@echo -n 'DEBUG_CFLAGS="$(strip $(DEBUG_CFLAGS))" '
+	@echo "$(strip $(BUILD_OPTIONS))"
+	@echo 'COPTS="$(strip $(COPTS))"'
+	@echo 'LDFLAGS="$(strip $(LDFLAGS))"'
+	@echo 'LDOPTS="$(strip $(LDOPTS))"'
+	@echo 'OPTIONS_OBJS="$(strip $(OPTIONS_OBJS))"'
+	@echo 'OBJS="$(strip $(OBJS))"'