feature/android f92bdbc6775: Update Android port

[Po Lu]

branch: feature/android
commit f92bdbc67754c77afcae95cb1ab237e2c5053ab2
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Update Android port
    
    * exec/config.h.in: Update config.h.in.
    * exec/configure.ac: Check for stpcpy and stpncpy.
    * exec/exec.c (rpl_stpcpy, rpl_stpncpy): Define replacements
    when they are not present on the system.
    (process_program_header): Fill comment.
---
 exec/config.h.in  |   9 +++++
 exec/configure.ac |   2 +-
 exec/exec.c       | 103 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 109 insertions(+), 5 deletions(-)

diff --git a/exec/config.h.in b/exec/config.h.in
index d602d89a38e..c276ff3f1f7 100644
--- a/exec/config.h.in
+++ b/exec/config.h.in
@@ -38,6 +38,9 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>. */
 /* Define to number of the `exec' system call. */
 #undef EXEC_SYSCALL
 
+/* Define to 1 if you have the `getpagesize' function. */
+#undef HAVE_GETPAGESIZE
+
 /* Define to 1 if you have the <inttypes.h> header file. */
 #undef HAVE_INTTYPES_H
 
@@ -53,6 +56,12 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>. */
 /* Define to 1 if you have the <stdlib.h> header file. */
 #undef HAVE_STDLIB_H
 
+/* Define to 1 if you have the `stpcpy' function. */
+#undef HAVE_STPCPY
+
+/* Define to 1 if you have the `stpncpy' function. */
+#undef HAVE_STPNCPY
+
 /* Define to 1 if you have the <strings.h> header file. */
 #undef HAVE_STRINGS_H
 
diff --git a/exec/configure.ac b/exec/configure.ac
index 9763edc99f3..9b4bcebe34e 100644
--- a/exec/configure.ac
+++ b/exec/configure.ac
@@ -54,7 +54,7 @@ AC_TYPE_UINTPTR_T
 AC_TYPE_PID_T
 
 AC_HEADER_STDBOOL
-AC_CHECK_FUNC([getpagesize])
+AC_CHECK_FUNCS([getpagesize stpcpy stpncpy])
 
 AH_BOTTOM([
 #ifdef HAVE_STDBOOL_H
diff --git a/exec/exec.c b/exec/exec.c
index c7a73f221f5..df8c9430236 100644
--- a/exec/exec.c
+++ b/exec/exec.c
@@ -21,7 +21,6 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 
 #include <errno.h>
 #include <unistd.h>
-#include <string.h>
 #include <fcntl.h>
 #include <assert.h>
 #include <string.h>
@@ -48,6 +47,103 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 
 
 
+
+/* Define replacements for required string functions.  */
+
+#ifndef HAVE_STPCPY
+
+/* Copy SRC to DEST, returning the address of the terminating '\0' in
+   DEST.  */
+
+static char *
+rpl_stpcpy (char *dest, const char *src)
+{
+  register char *d;
+  register const char *s;
+
+  d = dest;
+  s = src;
+
+  do
+    *d++ = *s;
+  while (*s++ != '\0');
+
+  return d - 1;
+}
+
+#define stpcpy rpl_stpcpy
+#endif /* !HAVE_STPCPY */
+
+#ifndef HAVE_STPNCPY
+
+/* Copy no more than N bytes of SRC to DST, returning a pointer past
+   the last non-NUL byte written into DST.  */
+
+char *
+rpl_stpncpy (char *dest, const char *src, size_t n)
+{
+  char c, *s;
+  size_t n4;
+
+  s = dest;
+
+  if (n >= 4)
+    {
+      n4 = n >> 2;
+
+      for (;;)
+       {
+         c = *src++;
+         *dest++ = c;
+         if (c == '\0')
+           break;
+         c = *src++;
+         *dest++ = c;
+         if (c == '\0')
+           break;
+         c = *src++;
+         *dest++ = c;
+         if (c == '\0')
+           break;
+         c = *src++;
+         *dest++ = c;
+         if (c == '\0')
+           break;
+         if (--n4 == 0)
+           goto last_chars;
+       }
+      n -= dest - s;
+      goto zero_fill;
+    }
+
+ last_chars:
+  n &= 3;
+  if (n == 0)
+    return dest;
+
+  for (;;)
+    {
+      c = *src++;
+      --n;
+      *dest++ = c;
+      if (c == '\0')
+       break;
+      if (n == 0)
+       return dest;
+    }
+
+ zero_fill:
+  while (n-- > 0)
+    dest[n] = '\0';
+
+  return dest - 1;
+}
+
+#define stpncpy rpl_stpncpy
+#endif /* !HAVE_STPNCPY */
+
+
+
 /* Executable reading functions.
    These functions extract information from an executable that is
    about to be loaded.
@@ -624,9 +720,8 @@ process_program_header (const char *name, int fd,
       break;
 
     case 3: /* PT_INTERP */
-      /* This describes another executable that must be loaded.
-         Open the interpreter and process each of its headers
-         as well.  */
+      /* This describes another executable that must be loaded.  Open
+        the interpreter and process each of its headers as well.  */
       rc = process_interpreter (fd, header, entry);
       break;