Makefile.mk: drop Windows support

And DLL-support with it. This leaves `Makefile.mk` for MS-DOS and Amiga.

We recommend CMake instead. With unity mode it's much faster, and about
the same without.

Ref: https://github.com/curl/curl/pull/12221#issuecomment-1783761806
Reviewed-by: Daniel Stenberg
Closes #12224

docs/examples/Makefile.mk

@@ -26,10 +26,6 @@
 
 PROOT := ../..
 
-ifeq ($(findstring -static,$(CFG)),)
-  DYN := 1
-endif
-
 ### Common
 
 include $(PROOT)/lib/Makefile.mk
@@ -40,35 +36,17 @@ CPPFLAGS += -DCURL_NO_OLDIES
 LDFLAGS  += -L$(PROOT)/lib
 LIBS     := -lcurl $(LIBS)
 
-ifdef DYN
-  curl_DEPENDENCIES += $(PROOT)/lib/libcurl.dll.a
-else
-  curl_DEPENDENCIES := $(PROOT)/lib/libcurl.a
-  ifdef WIN32
-    CPPFLAGS += -DCURL_STATICLIB
-    LDFLAGS += -static
-  endif
-endif
-
-ifdef WIN32
-  LIBS += -lws2_32
-endif
-
 ### Sources and targets
 
 # Provides check_PROGRAMS
 include Makefile.inc
 
-ifdef WIN32
-check_PROGRAMS += synctime
-endif
-
 TARGETS := $(patsubst %,%$(BIN_EXT),$(strip $(check_PROGRAMS)))
 TOCLEAN := $(TARGETS)
 
 ### Rules
 
-%$(BIN_EXT): %.c $(curl_DEPENDENCIES)
-	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) $(CURL_LDFLAGS_BIN) $< -o $@ $(LIBS)
+%$(BIN_EXT): %.c $(PROOT)/lib/libcurl.a
+	$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) $< -o $@ $(LIBS)
 
 all: $(TARGETS)