Add --enable-msvc-debug-runtime to use that even without dbgutil

Adapt libxml2 build accordingly. It's MSVC_USE_DEBUG_RUNTIME we should
check to see whether the ICU libraries have a 'd' suffix in their
names, not ENABLE_DBGUTIL.

Change-Id: Ic817e3c15e7164478ae557627047d3793e3a88c7
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/194584
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com>
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/196618
Reviewed-by: Tor Lillqvist <tml@iki.fi>
Tested-by: Jenkins

configure.ac

@@ -1727,6 +1727,12 @@ AC_ARG_ENABLE(avahi,
         [Determines whether to use Avahi to advertise Impress to remote controls.])
 )
 
+AC_ARG_ENABLE(msvc-debug-runtime,
+    AS_HELP_STRING([--enable-msvc-debug-runtime],
+        [Determines whether to use the Microsoft Visual Studio debugging runtime.
+         Automatically turned on by --enable-dbgutil but not by --enable-debug])
+)
+
 AC_ARG_ENABLE(msvc-analyze,
     AS_HELP_STRING([--enable-msvc-analyze],
         [Determines whether to enable the Microsoft Visual Studio /analyze flag to provide additional warnings.])
@@ -4998,7 +5004,11 @@ if test -n "$enable_dbgutil" -a "$enable_dbgutil" != "no"; then
     fi
 else
     ENABLE_DBGUTIL=""
-    MSVC_USE_DEBUG_RUNTIME=""
+    if test "$enable_msvc_debug_runtime" = "yes"; then
+        MSVC_USE_DEBUG_RUNTIME="TRUE"
+    else
+        MSVC_USE_DEBUG_RUNTIME=""
+    fi
     AC_MSG_RESULT([no])
 fi
 AC_SUBST(ENABLE_DBGUTIL)

external/libxml2/ExternalProject_libxml2.mk

@@ -27,7 +27,7 @@ $(call gb_ExternalProject_get_state_target,libxml2,build):
 	$(call gb_ExternalProject_run,build,\
 		cscript /e:javascript configure.js \
 			iconv=no icu=yes sax1=yes $(if $(MSVC_USE_DEBUG_RUNTIME),cruntime=/MDd) \
-			$(if $(filter TRUE,$(ENABLE_DBGUTIL)),debug=yes) \
+			$(if $(filter TRUE,$(MSVC_USE_DEBUG_RUNTIME)),debug=yes) \
 		&& nmake \
 	,win32)
 	$(call gb_Trace_EndRange,libxml2,EXTERNAL)