Add build option to Makefile for removing static compile flags (#3026)

this make it possible to remove one patch file from
https://gitlab.alpinelinux.org/alpine/aports/-/tree/master/testing/woodpecker

Makefile

@@ -27,7 +27,11 @@ else
 	endif
 endif
 
-LDFLAGS := -s -w -extldflags "-static" -X go.woodpecker-ci.org/woodpecker/v2/version.Version=${VERSION}
+LDFLAGS := -X go.woodpecker-ci.org/woodpecker/v2/version.Version=${VERSION}
+STATIC_BUILD ?= true
+ifeq ($(STATIC_BUILD),true)
+	LDFLAGS := -s -w -extldflags "-static" $(LDFLAGS)
+endif
 CGO_ENABLED ?= 1 # only used to compile server
 
 HAS_GO = $(shell hash go > /dev/null 2>&1 && echo "GO" || echo "NOGO" )