Use a C99 flexible array member

...so the following strcpy does not cause a false abort under _FORTIFY_SOURCE=2

Change-Id: I395136f11020064766db76f87ed8f5b01c083c3a
Reviewed-on: https://gerrit.libreoffice.org/18681Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

rsc/source/rscpp/cpp.h

@@ -162,7 +162,7 @@ typedef struct defbuf
     char*           repl;           /* -> replacement       */
     int             hash;           /* Symbol table hash    */
     int             nargs;          /* For define(args)     */
-    char            name[1];        /* #define name         */
+    char            name[];         /* #define name         */
 } DEFBUF;
 
 /*

rsc/source/rscpp/cpp6.c

@@ -613,7 +613,7 @@ DEFBUF* defendel(char* name, int delete)
     }
     if (!delete)
     {
-        dp = (DEFBUF*) getmem(sizeof (DEFBUF) + size);
+        dp = (DEFBUF*) getmem(sizeof (DEFBUF) + size + 1);
         dp->link = *prevp;
         *prevp = dp;
         dp->hash = nhash;

solenv/gbuild/platform/com_MSC_defs.mk

@@ -81,6 +81,8 @@ gb_AFLAGS := $(AFLAGS)
 
 # C4189: 'identifier' : local variable is initialized but not referenced
 
+# C4200: nonstandard extension used : zero-sized array in struct/union
+
 # C4201: nonstandard extension used : nameless struct/union
 
 # C4242: 'identifier' : conversion from 'type1' to 'type2', possible
@@ -150,6 +152,7 @@ gb_CFLAGS := \
 	$(if $(filter 0,$(gb_DEBUGLEVEL)),-wd4100) \
 	-wd4127 \
 	$(if $(filter 0,$(gb_DEBUGLEVEL)),-wd4189) \
+	-wd4200 \
 	-wd4242 \
 	-wd4244 \
 	-wd4251 \