Revert "Mes C Library: m2/execve.c: Remove specialization."

This fixes

    gcc-lib/libc+gnu.c: At top level:
    gcc-lib/libc+gnu.c:2694:1: error: conflicting types for ‘execve’
     execve (char const *file_name, char **argv, char **env)
     ^~~~~~
    In file included from gcc-lib/libc+gnu.c:492:0:
    include/unistd.h:66:5: note: previous declaration of ‘execve’ was here
     int execve (char const *file, char *const argv[], char *const env[]);
         ^~~~~~

This reverts commit 828c27a073.

kaem.run

@@ -84,7 +84,7 @@ M2-Planet                                       \
     -f lib/linux/ioctl3.c                       \
     -f lib/m2/isatty.c                          \
     -f lib/linux/fork.c                         \
-    -f lib/linux/execve.c                       \
+    -f lib/m2/execve.c                          \
     -f lib/m2/execv.c                           \
     -f lib/m2/waitpid.c                         \
     -f lib/linux/gettimeofday.c                 \

lib/linux/execve.c

@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *
@@ -18,15 +18,11 @@
  * along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <mes/lib.h>
 #include <linux/syscall.h>
 #include <syscall.h>
 
 int
-execve (char const *file_name, char **argv, char **env)
+execve (char const *file_name, char *const argv[], char *const env[])
 {
-  long long_file_name = cast_voidp_to_long (file_name);
-  long long_argv = cast_voidp_to_long (argv);
-  long long_env = cast_voidp_to_long (env);
-  return _sys_call3 (SYS_execve, long_file_name, long_argv, long_env);
+  return _sys_call3 (SYS_execve, (long) file_name, (long) argv, (long) env);
 }

lib/m2/execve.c

@@ -0,0 +1,31 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of GNU Mes.
+ *
+ * GNU Mes is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * GNU Mes is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/syscall.h>
+#include <syscall.h>
+
+int
+execve (char const *file_name, char **argv, char **env)
+{
+  long long_file_name = file_name;
+  long long_argv = argv;
+  long long_env = env;
+  return _sys_call3 (SYS_execve, file_name, argv, env);
+}

simple.make

@@ -122,7 +122,7 @@ M2_SOURCES =					\
  lib/linux/ioctl3.c  				\
  lib/m2/isatty.c				\
  lib/linux/fork.c				\
- lib/linux/execve.c				\
+ lib/m2/execve.c				\
  lib/m2/execv.c					\
  lib/m2/waitpid.c				\
  lib/linux/gettimeofday.c			\