MSVC: using SOLARINC

--- curl/winbuild/MakefileBuild.vc.orig	2017-10-23 16:36:07.713550851 +0200
+++ curl/winbuild/MakefileBuild.vc	2017-10-23 16:38:19.301547594 +0200
@@ -52,7 +52,7 @@
 !ELSE
 CC_NODEBUG  = $(CC) /O2 /DNDEBUG
 CC_DEBUG    = $(CC) /Od /D_DEBUG /RTC1 /Z7 /LDd
-CFLAGS      = /I. /I ../lib /I../include /nologo /W4 /EHsc /FD /c /DBUILDING_LIBCURL
+CFLAGS      = /I. /I ../lib /I../include /nologo /W4 /EHsc /FD /c /DBUILDING_LIBCURL $(SOLARINC)
 !ENDIF
 
 LFLAGS     = /nologo /machine:$(MACHINE)
@@ -428,11 +428,11 @@
 # CURL_XX macros are for the curl.exe command
 
 !IF "$(DEBUG)"=="yes"
-RC_FLAGS = /d_DEBUG /Fo $@ $(LIBCURL_SRC_DIR)\libcurl.rc
+RC_FLAGS = $(SOLARINC) /d_DEBUG /Fo $@ $(LIBCURL_SRC_DIR)\libcurl.rc
 CURL_CC       = $(CC_DEBUG) $(RTLIB_DEBUG)
 CURL_RC_FLAGS = $(CURL_RC_FLAGS) /i../include /d_DEBUG /Fo $@ $(CURL_SRC_DIR)\curl.rc
 !ELSE
-RC_FLAGS = /Fo $@ $(LIBCURL_SRC_DIR)\libcurl.rc
+RC_FLAGS = $(SOLARINC) /Fo $@ $(LIBCURL_SRC_DIR)\libcurl.rc
 CURL_CC       = $(CC_NODEBUG) $(RTLIB)
 CURL_RC_FLAGS = $(CURL_RC_FLAGS) /i../include /Fo $@ $(CURL_SRC_DIR)\curl.rc
 !ENDIF