Windows : fix clang-cl build.

Disable lock elision, due to buggy intrin.h (_xbegin is misspelled)
Fix warnings.

client/mysqlslap.c

@@ -94,7 +94,7 @@
 
 #ifdef _WIN32
 #define srandom  srand
-#define random   rand
+#define random() (long)rand()
 #endif
 
 

sql/sql_yacc.yy

@@ -76,7 +76,7 @@
 /* warning C4102: 'yyexhaustedlab': unreferenced label */
 #pragma warning (disable : 4065 4102)
 #endif
-#ifdef __GNUC__
+#if defined (__GNUC__) || defined (__clang__)
 #pragma GCC diagnostic ignored "-Wunused-label" /* yyexhaustedlab: */
 #endif
 

storage/innobase/include/transactional_lock_guard.h

@@ -20,7 +20,7 @@ this program; if not, write to the Free Software Foundation, Inc.,
 
 #if defined __powerpc64__ && defined __clang__ && defined __linux__
 #elif defined __powerpc64__&&defined __GNUC__&&defined __linux__&&__GNUC__ > 4
-#elif defined _MSC_VER && (defined _M_IX86 || defined _M_X64)
+#elif defined _MSC_VER && (defined _M_IX86 || defined _M_X64) && !defined(__clang__)
 #elif defined __GNUC__ && (defined __i386__ || defined __x86_64__)
 # if __GNUC__ >= 8
 # elif defined __clang_major__ && __clang_major__ > 6