winbuild: add ENABLE_WEBSOCKETS option

Closes #13232

winbuild/Makefile.vc

@@ -116,6 +116,16 @@ ENABLE_OPENSSL_AUTO_LOAD_CONFIG = true
 ENABLE_OPENSSL_AUTO_LOAD_CONFIG = false
 !ENDIF
 
+!IFNDEF ENABLE_WEBSOCKETS
+ENABLE_WEBSOCKETS = false
+!ELSEIF "$(ENABLE_WEBSOCKETS)"=="yes"
+!UNDEF ENABLE_WEBSOCKETS
+ENABLE_WEBSOCKETS = true
+!ELSEIF "$(ENABLE_WEBSOCKETS)"=="no"
+!UNDEF ENABLE_WEBSOCKETS
+ENABLE_WEBSOCKETS = false
+!ENDIF
+
 !IFNDEF ENABLE_UNICODE
 USE_UNICODE = false
 !ELSEIF "$(ENABLE_UNICODE)"=="yes"

winbuild/MakefileBuild.vc

@@ -141,6 +141,9 @@ SSL_CFLAGS   = $(SSL_CFLAGS) /DCURL_DISABLE_OPENSSL_AUTO_LOAD_CONFIG
 !ENDIF
 !ENDIF
 
+!IF "$(ENABLE_WEBSOCKETS)"=="true"
+CFLAGS  = $(CFLAGS) /DUSE_WEBSOCKETS=1
+!ENDIF
 
 !IFDEF NGHTTP2_PATH
 NGHTTP2_INC_DIR  = $(NGHTTP2_PATH)\include

winbuild/README.md

@@ -101,6 +101,7 @@ where `<options>` is one or many of:
                                  - Enable loading OpenSSL configuration
                                    automatically, defaults to yes
  - `ENABLE_UNICODE=<yes/no>`     - Enable UNICODE support, defaults to no
+ - `ENABLE_WEBSOCKETS=<yes/no>`  - Enable Web Socket support, defaults to no
  - `GEN_PDB=<yes/no>`            - Generate External Program Database
                                    (debug symbols for release build)
  - `DEBUG=<yes/no>`              - Debug builds