Introduce wrapper for CreateProcess

This is a small refactoring that introduces a wrapper for the Windows
CreateProcess function.  This is done to make the next patch a bit
simpler.

gdb/nat/windows-nat.c

@@ -741,6 +741,57 @@ wait_for_debug_event (DEBUG_EVENT *event, DWORD timeout)
   return result;
 }
 
+/* Helper template for the CreateProcess wrappers.  */
+template<typename FUNC, typename CHAR, typename INFO>
+BOOL
+create_process_wrapper (FUNC *do_create_process, const CHAR *image,
+			CHAR *command_line, DWORD flags,
+			void *environment, const CHAR *cur_dir,
+			INFO *startup_info,
+			PROCESS_INFORMATION *process_info)
+{
+  return do_create_process (image,
+			    command_line, /* command line */
+			    nullptr,	  /* Security */
+			    nullptr,	  /* thread */
+			    TRUE,	  /* inherit handles */
+			    flags,	  /* start flags */
+			    environment,  /* environment */
+			    cur_dir,	  /* current directory */
+			    startup_info,
+			    process_info);
+}
+
+/* See nat/windows-nat.h.  */
+
+BOOL
+create_process (const char *image, char *command_line, DWORD flags,
+		void *environment, const char *cur_dir,
+		STARTUPINFOA *startup_info,
+		PROCESS_INFORMATION *process_info)
+{
+  return create_process_wrapper (CreateProcessA, image, command_line, flags,
+				 environment, cur_dir,
+				 startup_info, process_info);
+}
+
+#ifdef __CYGWIN__
+
+/* See nat/windows-nat.h.  */
+
+BOOL
+create_process (const wchar_t *image, wchar_t *command_line, DWORD flags,
+		void *environment, const wchar_t *cur_dir,
+		STARTUPINFOW *startup_info,
+		PROCESS_INFORMATION *process_info);
+{
+  return create_process_wrapper (CreateProcessW, image, command_line, flags,
+				 environment, cur_dir,
+				 startup_info, process_info);
+}
+
+#endif /* __CYGWIN__ */
+
 /* Define dummy functions which always return error for the rare cases where
    these functions could not be found.  */
 template<typename... T>

gdb/nat/windows-nat.h

@@ -294,6 +294,21 @@ extern BOOL continue_last_debug_event (DWORD continue_status,
 
 extern BOOL wait_for_debug_event (DEBUG_EVENT *event, DWORD timeout);
 
+/* Wrappers for CreateProcess.  */
+
+extern BOOL create_process (const char *image, char *command_line,
+			    DWORD flags, void *environment,
+			    const char *cur_dir,
+			    STARTUPINFOA *startup_info,
+			    PROCESS_INFORMATION *process_info);
+#ifdef __CYGWIN__
+extern BOOL create_process (const wchar_t *image, wchar_t *command_line,
+			    DWORD flags, void *environment,
+			    const wchar_t *cur_dir,
+			    STARTUPINFOW *startup_info,
+			    PROCESS_INFORMATION *process_info);
+#endif /* __CYGWIN__ */
+
 #define AdjustTokenPrivileges		dyn_AdjustTokenPrivileges
 #define DebugActiveProcessStop		dyn_DebugActiveProcessStop
 #define DebugBreakProcess		dyn_DebugBreakProcess

gdb/windows-nat.c

@@ -78,12 +78,10 @@ using namespace windows_nat;
 static windows_process_info windows_process;
 
 #undef STARTUPINFO
-#undef CreateProcess
 
 #ifndef __CYGWIN__
 # define __PMAX	(MAX_PATH + 1)
 # define STARTUPINFO STARTUPINFOA
-# define CreateProcess CreateProcessA
 #else
 # define __PMAX	PATH_MAX
 /* The starting and ending address of the cygwin1.dll text segment.  */
@@ -92,7 +90,6 @@ static windows_process_info windows_process;
 #   define __USEWIDE
     typedef wchar_t cygwin_buf_t;
 #   define STARTUPINFO STARTUPINFOW
-#   define CreateProcess CreateProcessW
 #endif
 
 static int have_saved_context;	/* True if we've saved context from a
@@ -2494,17 +2491,9 @@ windows_nat_target::create_inferior (const char *exec_file,
     }
 
   windows_init_thread_list ();
-  ret = CreateProcess (0,
-		       args,	/* command line */
-		       NULL,	/* Security */
-		       NULL,	/* thread */
-		       TRUE,	/* inherit handles */
-		       flags,	/* start flags */
-		       w32_env,	/* environment */
-		       inferior_cwd != NULL ? infcwd : NULL, /* current
-								directory */
-		       &si,
-		       &pi);
+  ret = create_process (args, flags, w32_env,
+			inferior_cwd != nullptr ? infcwd : nullptr,
+			&si, &pi);
   if (w32_env)
     /* Just free the Win32 environment, if it could be created. */
     free (w32_env);
@@ -2618,11 +2607,8 @@ windows_nat_target::create_inferior (const char *exec_file,
   *temp = 0;
 
   windows_init_thread_list ();
-  ret = CreateProcessA (0,
+  ret = create_process (nullptr, /* image */
 			args,	/* command line */
-			NULL,	/* Security */
-			NULL,	/* thread */
-			TRUE,	/* inherit handles */
 			flags,	/* start flags */
 			w32env,	/* environment */
 			inferior_cwd, /* current directory */

gdbserver/win32-low.cc

@@ -578,11 +578,8 @@ create_process (const char *program, char *args,
   strcpy (program_and_args, program);
   strcat (program_and_args, " ");
   strcat (program_and_args, args);
-  ret = CreateProcessA (program,           /* image name */
+  ret = create_process (program,           /* image name */
 			program_and_args,  /* command line */
-			NULL,              /* security */
-			NULL,              /* thread */
-			TRUE,              /* inherit handles */
 			flags,             /* start flags */
 			NULL,              /* environment */
 			/* current directory */