Adding a --use-threads options which I believe will allow it to be ported to windows.

client/Makefile.am:
  Adding pthread flag
client/client_priv.h:
  New option to use theads.
client/mysqlslap.c:
  Adding support to optionally use threads (which should allow it to work with windows)

client/Makefile.am

@@ -48,6 +48,7 @@ mysqlbinlog_SOURCES =		mysqlbinlog.cc $(top_srcdir)/mysys/mf_tempdir.c \
 				$(top_srcdir)/mysys/my_vle.c \
 				$(top_srcdir)/mysys/base64.c
 mysqlbinlog_LDADD =		$(LDADD) $(CXXLDFLAGS)
+mysqlslap_LDADD =		$(LDADD) $(CXXLDFLAGS) -lpthread
 mysqltestmanager_pwgen_SOURCES =   mysqlmanager-pwgen.c 
 mysqltestmanagerc_SOURCES=      mysqlmanagerc.c $(yassl_dummy_link_fix)
 mysqlcheck_SOURCES=             mysqlcheck.c $(yassl_dummy_link_fix)

client/client_priv.h

@@ -53,6 +53,7 @@ enum options_client
   OPT_MYSQL_ONLY_PRINT,
   OPT_MYSQL_LOCK_DIRECTORY,
   OPT_MYSQL_SLAP_SLAVE,
+  OPT_USE_THREADS,
   OPT_MYSQL_NUMBER_OF_QUERY,
   OPT_MYSQL_PRESERVE_SCHEMA,
   OPT_IGNORE_TABLE,OPT_INSERT_IGNORE,OPT_SHOW_WARNINGS,OPT_DROP_DATABASE,

client/mysqlslap.c

@@ -87,6 +87,7 @@ TODO:
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <ctype.h>
+#include <my_pthread.h>
 
 #define MYSLAPLOCK "/myslaplock.lck"
 #define MYSLAPLOCK_DIR "/tmp"
@@ -132,6 +133,7 @@ static uint opt_protocol= 0;
 
 static int get_options(int *argc,char ***argv);
 static uint opt_mysql_port= 0;
+static uint opt_use_threads;
 
 static const char *load_default_groups[]= { "mysqlslap","client",0 };
 
@@ -151,6 +153,13 @@ struct stats {
   unsigned long long rows;
 };
 
+typedef struct thread_context thread_context;
+
+struct thread_context {
+  statement *stmt;
+  ulonglong limit;
+};
+
 typedef struct conclusions conclusions;
 
 struct conclusions {
@@ -184,7 +193,7 @@ static int create_schema(MYSQL *mysql, const char *db, statement *stmt,
               statement *engine_stmt);
 static int run_scheduler(stats *sptr, statement *stmts, uint concur, 
                          ulonglong limit);
-int run_task(statement *stmt, ulonglong limit);
+int run_task(thread_context *con);
 void statement_cleanup(statement *stmt);
 
 static const char ALPHANUMERICS[]=
@@ -440,6 +449,10 @@ static struct my_option my_long_options[] =
   {"socket", 'S', "Socket file to use for connection.",
     (gptr*) &opt_mysql_unix_port, (gptr*) &opt_mysql_unix_port, 0, GET_STR,
     REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
+  {"use-threads", OPT_USE_THREADS,
+    "Use pthread calls instead of fork() calls (default on Windows)",
+      (gptr*) &opt_use_threads, (gptr*) &opt_use_threads, 0, 
+      GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
 #include <sslopt-longopts.h>
 #ifndef DONT_ALLOW_USER_CHANGE
   {"user", 'u', "User for login if not current user.", (gptr*) &user,
@@ -930,8 +943,11 @@ run_scheduler(stats *sptr, statement *stmts, uint concur, ulonglong limit)
   uint x;
   File lock_file;
   struct timeval start_time, end_time;
+  thread_context con;
   DBUG_ENTER("run_scheduler");
 
+  con.stmt= stmts;
+  con.limit= limit;
 
   lock_file= my_open(lock_file_str, O_CREAT|O_WRONLY|O_TRUNC, MYF(0));
 
@@ -943,6 +959,29 @@ run_scheduler(stats *sptr, statement *stmts, uint concur, ulonglong limit)
       exit(0);
     }
 
+  if (opt_use_threads)
+  {
+    pthread_t mainthread;            /* Thread descriptor */
+    pthread_attr_t attr;          /* Thread attributes */
+
+    for (x= 0; x < concur; x++)
+    {
+      pthread_attr_init(&attr);
+      pthread_attr_setdetachstate(&attr,
+                                   PTHREAD_CREATE_DETACHED);
+
+      /* now create the thread */
+      if (pthread_create(&mainthread, &attr, (void *)run_task, 
+                         (void *)&con) != 0)
+      {
+        fprintf(stderr,"%s: Could not create thread\n",
+                my_progname);
+        exit(0);
+      }
+    }
+  }
+  else
+  {
     for (x= 0; x < concur; x++)
     {
       int pid;
@@ -958,7 +997,7 @@ run_scheduler(stats *sptr, statement *stmts, uint concur, ulonglong limit)
           fprintf(stderr,
                   "%s: fork returned 0, calling task pid %d gid %d\n",
                   my_progname, pid, getgid());
-      run_task(stmts, limit);
+        run_task(&con);
         exit(0);
         break;
       case -1:
@@ -979,6 +1018,8 @@ run_scheduler(stats *sptr, statement *stmts, uint concur, ulonglong limit)
         break;
       }
     }
+  }
+
   /* Lets release use some clients! */
   if (!opt_slave)
     my_lock(lock_file, F_UNLCK, 0, F_TO_EOF, MYF(0));
@@ -987,6 +1028,11 @@ run_scheduler(stats *sptr, statement *stmts, uint concur, ulonglong limit)
 
   my_close(lock_file, MYF(0));
 
+  if (opt_use_threads)
+  {
+  }
+  else
+  {
 WAIT:
     while (x--)
     {
@@ -994,6 +1040,7 @@ WAIT:
       pid= wait(&status);
       DBUG_PRINT("info", ("Parent: child %d status %d", pid, status));
     }
+  }
   gettimeofday(&end_time, NULL);
 
   sptr->timing= timedif(end_time, start_time);
@@ -1004,7 +1051,7 @@ WAIT:
 }
 
 int
-run_task(statement *qstmt, ulonglong limit)
+run_task(thread_context *con)
 {
   ulonglong counter= 0, queries;
   File lock_file;
@@ -1014,7 +1061,7 @@ run_task(statement *qstmt, ulonglong limit)
   statement *ptr;
 
   DBUG_ENTER("run_task");
-  DBUG_PRINT("info", ("task script \"%s\"", qstmt->string));
+  DBUG_PRINT("info", ("task script \"%s\"", con->stmt->string));
 
   mysql_init(&mysql);
 
@@ -1036,7 +1083,7 @@ run_task(statement *qstmt, ulonglong limit)
   queries= 0; 
 
 limit_not_met:
-    for (ptr= qstmt; ptr && ptr->length; ptr= ptr->next)
+    for (ptr= con->stmt; ptr && ptr->length; ptr= ptr->next)
     {
       if (opt_only_print) 
       {
@@ -1060,11 +1107,11 @@ limit_not_met:
       }
       queries++;
 
-      if (limit && queries == limit)
+      if (con->limit && queries == con->limit)
         DBUG_RETURN(0);
     }
 
-  if (limit && queries < limit)
+  if (con->limit && queries < con->limit)
     goto limit_not_met;
 
   my_lock(lock_file, F_UNLCK, 0, F_TO_EOF, MYF(0));