make: improve re2/wasm check (#3335)

Makefile

@@ -22,7 +22,7 @@ BUILD_RE2_WASM ?= 0
 # for your distribution (look for libre2.a). See the Dockerfile for an example of how to build it.
 BUILD_STATIC ?= 0
 
-# List of plugins to build
+# List of notification plugins to build
 PLUGINS ?= $(patsubst ./cmd/notification-%,%,$(wildcard ./cmd/notification-*))
 
 #--------------------------------------
@@ -86,42 +86,40 @@ export CGO_LDFLAGS_ALLOW=-Wl,--(push|pop)-state.*
 # this will be used by Go in the make target, some distributions require it
 export PKG_CONFIG_PATH:=/usr/local/lib/pkgconfig:$(PKG_CONFIG_PATH)
 
+#--------------------------------------
+#
+# Choose the re2 backend.
+#
+
 ifeq ($(call bool,$(BUILD_RE2_WASM)),0)
 ifeq ($(PKG_CONFIG),)
   $(error "pkg-config is not available. Please install pkg-config.")
 endif
 
 ifeq ($(RE2_CHECK),)
 RE2_FAIL := "libre2-dev is not installed, please install it or set BUILD_RE2_WASM=1 to use the WebAssembly version"
+# if you prefer to build WASM instead of a critical error, comment out RE2_FAIL and uncomment RE2_MSG.
+# RE2_MSG := Fallback to WebAssembly regexp library. To use the C++ version, make sure you have installed libre2-dev and pkg-config.
 else
 # += adds a space that we don't want
 GO_TAGS := $(GO_TAGS),re2_cgo
 LD_OPTS_VARS += -X '$(GO_MODULE_NAME)/pkg/cwversion.Libre2=C++'
+RE2_MSG := Using C++ regexp library
 endif
-endif
-
-# Build static to avoid the runtime dependency on libre2.so
-ifeq ($(call bool,$(BUILD_STATIC)),1)
-BUILD_TYPE = static
-EXTLDFLAGS := -extldflags '-static'
 else
-BUILD_TYPE = dynamic
-EXTLDFLAGS :=
+RE2_MSG := Using WebAssembly regexp library
 endif
 
-# Build with debug symbols, and disable optimizations + inlining, to use Delve
-ifeq ($(call bool,$(DEBUG)),1)
-STRIP_SYMBOLS :=
-DISABLE_OPTIMIZATION := -gcflags "-N -l"
+ifeq ($(call bool,$(BUILD_RE2_WASM)),1)
 else
-STRIP_SYMBOLS := -s
-DISABLE_OPTIMIZATION :=
+ifneq (,$(RE2_CHECK))
+endif
 endif
 
 #--------------------------------------
-
+#
 # Handle optional components and build profiles, to save space on the final binaries.
-
+#
 # Keep it safe for now until we decide how to expand on the idea. Either choose a profile or exclude components manually.
 # For example if we want to disable some component by default, or have opt-in components (INCLUDE?).
 
@@ -182,6 +180,23 @@ endif
 
 #--------------------------------------
 
+ifeq ($(call bool,$(BUILD_STATIC)),1)
+BUILD_TYPE = static
+EXTLDFLAGS := -extldflags '-static'
+else
+BUILD_TYPE = dynamic
+EXTLDFLAGS :=
+endif
+
+# Build with debug symbols, and disable optimizations + inlining, to use Delve
+ifeq ($(call bool,$(DEBUG)),1)
+STRIP_SYMBOLS :=
+DISABLE_OPTIMIZATION := -gcflags "-N -l"
+else
+STRIP_SYMBOLS := -s
+DISABLE_OPTIMIZATION :=
+endif
+
 export LD_OPTS=-ldflags "$(STRIP_SYMBOLS) $(EXTLDFLAGS) $(LD_OPTS_VARS)" \
 	-trimpath -tags $(GO_TAGS) $(DISABLE_OPTIMIZATION)
 
@@ -197,17 +212,13 @@ build: build-info crowdsec cscli plugins  ## Build crowdsec, cscli and plugins
 .PHONY: build-info
 build-info:  ## Print build information
 	$(info Building $(BUILD_VERSION) ($(BUILD_TAG)) $(BUILD_TYPE) for $(GOOS)/$(GOARCH))
-	$(info Excluded components: $(EXCLUDE_LIST))
+	$(info Excluded components: $(if $(EXCLUDE_LIST),$(EXCLUDE_LIST),none))
 
 ifneq (,$(RE2_FAIL))
 	$(error $(RE2_FAIL))
 endif
 
-ifneq (,$(RE2_CHECK))
-	$(info Using C++ regexp library)
-else
-	$(info Fallback to WebAssembly regexp library. To use the C++ version, make sure you have installed libre2-dev and pkg-config.)
-endif
+	$(info $(RE2_MSG))
 
 ifeq ($(call bool,$(DEBUG)),1)
 	$(info Building with debug symbols and disabled optimizations)